Broadcast signal transmitting method, broadcast signal receiving method, broadcast signal transmitting apparatus, and broadcast signal receiving apparatus

ABSTRACT

Provided is a method for transmitting a broadcast signal. The method includes generating a plurality of input packets including broadcast data, generating at least one link layer packet using the input packets, wherein a header of the link layer packet includes packet type information and packet configuration information, the packet type information indicates a type of an input packet included in a payload of the link layer packet, and the packet configuration information indicates a payload configuration of the link layer packet, generating a broadcast signal using the link layer packet, and transmitting the broadcast signal.

This application is a 35 USC § 371 National Stage entry of InternationalApplication No. PCT/KR2015/007918 filed on Jul. 29, 2015, which claimspriority to US Provisional Application No. 62/031,873 filed on Aug. 1,2014, and US Provisional Application No. 62/036,610 filed on Aug. 12,2014, all of which are incorporated by reference in their entiretyherein.

TECHNICAL FIELD

The present invention relates to broadcast signal transmitting method,broadcast signal receiving method, broadcast signal transmittingapparatus, and broadcast signal receiving apparatus.

BACKGROUND ART

Recently, broadcast environments using an Internet protocol (IP) in adigital broadcast system have become popular. There is a forecast that ahybrid broadcast system for providing a broadcast service in conjunctionwith a broadcast network and the Internet is established as anext-generation broadcast system. Accordingly, methods for preservingand developing technologies of a digital broadcast system using atypical IP have been considered. However, it takes a significant longtime to completely convert a conventional broadcast system using atypical MPEG-2 TS into an IP broadcast system in terms of industry orstrategy, and thus a broadcast system that simultaneously supports IPand MPEG-2 TS needs to be considered.

DISCLOSURE Technical Problem

An object of the present invention devised to solve the problem lies ina broadcast signal transmitting method, broadcast signal receivingmethod, broadcast signal transmitting apparatus, and broadcast signalreceiving apparatus.

Technical Solution

The object of the present invention can be achieved by providing amethod for transmitting a broadcast signal including generating aplurality of input packets comprising broadcast data, generating atleast one link layer packet using the input packets, wherein a header ofthe link layer packet comprises packet type information and packetconfiguration information, the packet type information indicates a typeof an input packet included in a payload of the link layer packet, andthe packet configuration information indicates a payload configurationof the link layer packet, generating a broadcast signal using the linklayer packet, and transmitting the broadcast signal.

When the payload comprises one of segmented segments of an input packet,the header may further include information of a segment sequencer numberindicating an order in a corresponding input packet of a segmentincluded in the link layer packet.

In another aspect of the present invention, provided herein is anapparatus for transmitting a broadcast signal including a first modulefor generating a plurality of input packets comprising broadcast data, asecond module for generating at least one link layer packet using theinput packets, wherein a header of the link layer packet comprisespacket type information and packet configuration information, the packettype information indicates a type of an input packet included in apayload of the link layer packet, and the packet configurationinformation indicates a payload configuration of the link layer packet,a third module for generating a broadcast signal using the link layerpacket, and a fourth module for transmitting the broadcast signal.

When the payload comprises one of segmented segments of an input packet,the header may further include information of a segment sequencer numberindicating an order in a corresponding input packet of a segmentincluded in the link layer packet.

Advantageous Effects

The present invention provides an effective broadcast signaltransmitting method, an effective broadcast signal receiving method, aneffective broadcast signal transmitting apparatus, and an effectivebroadcast signal receiving apparatus.

In addition, the present invention may enhance data transfer efficiencyand enhance robustness for transmitting and receiving a broadcastsignal.

DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram illustrating a protocol stack for a hybrid-basednext-generation broadcast system according to an embodiment of thepresent invention.

FIG. 2 is a diagram illustrating an interface of a link layer accordingto an embodiment of the present invention.

FIG. 3 is a diagram illustrating a structure of a packet of a link layeraccording to an embodiment of the present invention.

FIG. 4 is a diagram illustrating a packet type according to a packettype element according to an embodiment of the present invention.

FIG. 5 is a diagram illustrating a structure of a header of a link layerwhen an IP packet is transmitted to a link layer, according to anembodiment of the present invention.

FIG. 6 is a diagram illustrating meaning of a C/S field andconfiguration information of a header according to an embodiment of thepresent invention.

FIG. 7 is a diagram illustrating meaning according to a value of a countfield according to an embodiment of the present invention.

FIG. 8 is a diagram illustrating the meaning and segment lengthaccording to a value of a Seg_Len_ID field according to an embodiment ofthe present invention.

FIG. 9 is a diagram illustrating a procedure of encapsulating a normalpacket and an equation of a length of a link layer packet according toan embodiment of the present invention.

FIG. 10 is a diagram illustrating a procedure for encapsulating aconcatenated packet and an equation of a length of a link layer packetaccording to an embodiment of the present invention.

FIG. 11 is a diagram illustrating a procedure for obtaining a length ofa concatenated packet including an IPv4 packet and an equation forcalculating an offset value at which a length field of an IP packet ispositioned according to an embodiment of the present invention.

FIG. 12 is a diagram illustrating a procedure for calculating a lengthof a concatenated packet including an IPv6 packet and an equation forcalculating an offset value in which a length field of an IP packet ispositioned, according to an embodiment of the present invention.

FIG. 13 is a diagram illustrating a procedure for encapsulating asegmented packet according to an embodiment of the present invention.

FIG. 14 is a diagram illustrating a procedure for segmenting an IPpacket and header information of a link layer packet according to themethod, according to an embodiment of the present invention.

FIG. 15 is a diagram illustrating a procedure for segmenting an IPpacket including cyclic redundancy check (CRC) according to anembodiment of the present invention.

FIG. 16 is a diagram illustrating a header structure of a link layerpacket when an MPEG-2 transport stream (TS) is input to a link layer,according to an embodiment of the present invention.

FIG. 17 is a diagram illustrating the number of MPEG-2 TS packetsincluded in a payload of a link layer packet according to a value of acount field, according to an embodiment of the present invention.

FIG. 18 is a diagram illustrating a header of an MPEG-2 TS packetaccording to an embodiment of the present invention.

FIG. 19 is a diagram illustrating a procedure for changing use of atransport EI field by a transmitter according to an embodiment of thepresent invention.

FIG. 20 is a diagram illustrating a procedure for encapsulating anMPEG-2 TS packet according to an embodiment of the present invention.

FIG. 21 is a diagram illustrating a procedure for encapsulating MPEG-2TS packets having the same PIDs, according to an embodiment of thepresent invention.

FIG. 22 is a diagram illustrating an equation for obtaining a length ofa link layer packet during a common PID reduction procedure and a commonPID reduction procedure, according to an embodiment of the presentinvention.

FIG. 23 is a diagram illustrating the number of concatenated MPEG-2 TSpackets according to a value of a count field and a length of a linklayer packet according to the number when common PID reduction isapplied, according to an embodiment of the present invention.

FIG. 24 is a diagram illustrating a method for encapsulating an MPEG-2TS packet including a null packet, according to an embodiment of thepresent invention.

FIG. 25 is a diagram illustrating a procedure for processing anindicator for counting deleted null packets and an equation forobtaining a length of a link layer packet during the procedure,according to an embodiment of the present invention.

FIG. 26 is a diagram illustrating a procedure for encapsulating anMPEG-2 TS packet including a null packet, according to anotherembodiment of the present invention.

FIG. 27 is a diagram illustrating a procedure for encapsulating MPEG-2TS packets including the same packet identifier (PID) in a streamincluding a null packet, according to an embodiment of the presentinvention.

FIG. 28 is a diagram illustrating an equation for obtaining a length ofa link layer packet while MPEG-2 TS packets including the same packetidentifier (PID) are encapsulated in a stream including a null packet,according to an embodiment of the present invention.

FIG. 29 is a diagram illustrating a configuration of a link layer packetfor signaling transmission, according to an embodiment of the presentinvention.

FIG. 30 is a diagram illustrating a configuration of a link layer packetfor transmission of a framed packet, according to an embodiment of thepresent invention.

FIG. 31 is a diagram illustrating syntax of a framed packet, accordingto an embodiment of the present invention.

FIG. 32 is a diagram illustrating a receiver of a next-generationbroadcast system, according to an embodiment of the present invention.

FIG. 33 is a diagram illustrating normal format of a section table,according to an embodiment of the present invention.

FIG. 34 is a diagram illustrating a structure of a link layer packet fortransmission of signaling, according to an embodiment of the presentinvention.

FIG. 35 is a diagram illustrating meaning of a value of a signaling typefield and information about a fixed header and extended headersubsequent to the signaling type field, according to an embodiment ofthe present invention.

FIG. 36 is a diagram illustrating the number of descriptors included ina payload of a link layer packet according to a concatenation countvalue, according to an embodiment of the present invention.

FIG. 37 is a diagram illustrating a procedure for encapsulating asection table in a payload when signaling information input to a payloadof a link layer packet is a section table, according to an embodiment ofthe present invention.

FIG. 38 is a diagram illustrating syntax of a network information table(NIT) according to an embodiment of the present invention.

FIG. 39 is a diagram illustrating syntax of a delivery system descriptorincluded in a network information table (NIT), according to anembodiment of the present invention.

FIG. 40 is a diagram illustrating syntax of a fast information table(FIT) according to an embodiment of the present invention.

FIG. 41 is a diagram illustrating a procedure for encapsulating adescriptor in a payload when signaling information input to a payload ofa link layer packet is a descriptor, according to an embodiment of thepresent invention.

FIG. 42 is a diagram illustrating syntax of fast information descriptoraccording to an embodiment of the present invention.

FIG. 43 is a diagram illustrating a delivery system descriptor accordingto an embodiment of the present invention.

FIG. 44 is a diagram illustrating a procedure for encapsulating oneGSE-LLC item in a payload of one link layer packet when signalinginformation input to a payload of a link layer packet is a GSE-LLC typeused in the DVB-GSE standard, according to an embodiment of the presentinvention.

FIG. 45 is a diagram illustrating a procedure for encapsulating oneGSE-LLC data item in payloads of a plurality of link layer packets whensignaling information input to a payload of a link layer packet is aGSE-LLC type used in the DVB-GSE standard, according to an embodiment ofthe present invention.

FIG. 46 is a diagram illustrating a method for transmitting signalinginformation according to an embodiment of the present invention.

FIG. 47 is a diagram illustrating a header of a link layer packet forRoHC transmission, according to an embodiment of the present invention.

FIG. 48 is a diagram illustrating a method for transmitting an RoHCpacket through a link layer packet according to Embodiment #1 of thepresent invention.

FIG. 49 is a diagram of a method for transmitting an RoHC packet througha link layer packet according to Embodiment #2 of the present invention.

FIG. 50 is a diagram illustrating a method for transmitting an RoHCpacket of a link layer packet according to Embodiment #3 of the presentinvention.

FIG. 51 is a diagram illustrating a method for transmitting a RoHCpacket through a link layer packet according to Embodiment #4 of thepresent invention.

FIG. 52 is a diagram illustrating a header of a link layer packet forRoHC transmission when MTU is 1500, according to an embodiment of thepresent invention.

FIG. 53 is a diagram illustrating a method for transmitting a RoHCpacket through a link layer packet when a MTU is 1500 according toEmbodiment #1 of the present invention.

FIG. 54 is a diagram illustrating a method for transmitting an RoHCpacket through a link layer packet when a MTU is 1500 according toEmbodiment #2 of the present invention.

FIG. 55 is a diagram illustrating a method for transmitting an RoHCpacket through a link layer packet when a MTU is 1500 according toEmbodiment #3 of the present invention.

FIG. 56 is a diagram illustrating a method for transmitting an RoHCpacket through a link layer packet when a MTU is 1500 according toEmbodiment #4 of the present invention.

FIG. 57 is a diagram illustrating a method for transmitting an RoHCpacket through a link layer packet when a MTU is 1500 according toEmbodiment #5 of the present invention.

FIG. 58 is a diagram illustrating a method for transmitting an RoHCpacket through a link layer packet when a MUT is 1500 according toEmbodiment #6 of the present invention.

FIG. 59 is a diagram illustrating a method for transmitting an RoHCpacket through a link layer packet when a MTU is 1500 according toEmbodiment #7 of the present invention.

FIG. 60 is a diagram illustrating a configuration of a header of a linklayer packet when an IP packet is transmitted to a link layer, accordingto another embodiment of the present invention.

FIG. 61 is a diagram illustrating information indicated by each field ina header of a link layer packet when an IP packet is transmitted to alink layer, according to another embodiment of the present invention.

FIG. 62 is a diagram illustrating the case in which one IP packet isincluded in a link layer payload with respect to a header of a linklayer packet when an IP packet is transmitted to a link layer, accordingto another embodiment of the present invention.

FIG. 63 is a diagram illustrating the case in which a plurality of IPpackets are concatenated and included in a link layer payload withrespect to a header of a link layer packet when an IP packet istransmitted to a link layer, according to another embodiment of thepresent invention.

FIG. 64 is a diagram illustrating the case in which one IP packet issegmented and included in a link layer payload with respect to a headerof a link layer packet when an IP packet is transmitted to a link layer,according to another embodiment of the present invention.

FIG. 65 is a diagram illustrating link layer packets having segmentedsegments with respect to a header of a link layer packet when an IPpacket is transmitted to a link layer, according to another embodimentof the present invention.

FIG. 66 is a diagram illustrating a method for using CRC encoding withrespect to a header of a link layer packet when an IP packet istransmitted to a link layer, according to another embodiment of thepresent invention.

FIG. 67 is a diagram illustrating a configuration of a link layer packetwhen signaling information is transmitted to a link layer according toanother embodiment of the present invention.

FIG. 68 is a diagram illustrating information indicated by fields withrespect to a configuration of a link layer packet when signalinginformation is transmitted to a link layer, according to anotherembodiment of the present invention.

FIG. 69 is a diagram illustrating a configuration of a link layer packetwhen signaling information is one section table with respect to theconfiguration of the link layer packet when signaling information istransmitted to a link layer, according to another embodiment of thepresent invention.

FIG. 70 is a diagram illustrating a configuration of a link layer packetwhen signaling information is one descriptor with respect to theconfiguration of the link layer packet when signaling information istransmitted to a link layer, according to another embodiment of thepresent invention.

FIG. 71 is a diagram illustrating a configuration of a link layer packetwhen signaling information is a plurality of descriptors with respect tothe configuration of the link layer packet when signaling information istransmitted to a link layer, according to another embodiment of thepresent invention.

FIG. 72 is a diagram illustrating a configuration of a link layer packetwhen signaling information is a plurality of section tables with respectto the configuration of the link layer packet when signaling informationis transmitted to a link layer, according to another embodiment of thepresent invention.

FIG. 73 is a diagram illustrating a configuration of a link layer packetwhen signaling information does not have a separate length value withrespect to the configuration of the link layer packet when signalinginformation is transmitted to a link layer, according to anotherembodiment of the present invention.

FIG. 74 is a diagram illustrating a configuration of a link layer packetwhen one signaling information item is segmented to a plurality ofsegments with respect to the configuration of the link layer packet whensignaling information is transmitted to a link layer, according toanother embodiment of the present invention.

FIG. 75 is a diagram illustrating a method for transmitting a broadcastsignal according to an embodiment of the present invention.

FIG. 76 is a diagram illustrating an apparatus for transmitting abroadcast signal according to an embodiment of the present invention.

FIG. 77 is a diagram illustrating a configuration of a link layer packetwhen signaling information is transmitted to a link layer, according toanother embodiment of the present invention.

FIG. 78 is a diagram illustrating a Signaling_Class field when signalinginformation is transmitted to a link layer, according to anotherembodiment of the present invention.

FIG. 79 is a diagram illustrating a Signaling_Class field and anInformation_Type field when signaling information is transmitted to alink layer, according to another embodiment of the present invention.

FIG. 80 is a diagram illustrating a Signaling_Format field whensignaling information is transmitted to a link layer, according toanother embodiment of the present invention.

FIG. 81 is a diagram illustrating the case in which a plurality ofsignaling information items are concatenated with respect to aconfiguration of a link layer packet when signaling information istransmitted to a link layer, according to another embodiment of thepresent invention.

FIG. 82 is a diagram illustrating a case in which a plurality ofsignaling information items are concatenated with respect to aconfiguration of a link layer packet when signaling information istransmitted to a link layer, according to another embodiment of thepresent invention.

FIG. 83 is a diagram illustrating a configuration of a link layer packetwhen a framed packet is transmitted to a link layer, according toanother embodiment of the present invention.

FIG. 84 is a diagram illustrating ethernet_type field when a framedpacket is transmitted to a link layer, according to another embodimentof the present invention.

FIG. 85 is a diagram illustrating the case in which one input packet isincluded in a link layer payload when a framed packet is transmitted toa link layer, according to another embodiment of the present invention.

FIG. 86 is a diagram illustrating the case in which a plurality of inputpackets are concatenated and included in a link layer payload when aframed packet is transmitted to a link layer, according to anotherembodiment of the present invention.

FIG. 87 is a diagram illustrating the case in which one input packet issegmented and included in a link layer payload when a framed packet istransmitted to a link layer, according to another embodiment of thepresent invention.

FIG. 88 is a diagram illustrating a method for transmitting a broadcastsignal according to an embodiment of the present invention.

FIG. 89 is a diagram illustrating an apparatus for transmitting abroadcast signal according to an embodiment of the present invention.

BEST MODE

Reference will now be made in detail to the embodiments, examples ofwhich are illustrated in the accompanying drawings. However, theembodiments should not be construed as limited to the exemplaryembodiments set forth herein

Although the terms used in the present invention are selected fromgenerally known and used terms, terms used herein may be variabledepending on operator's intention or customs in the art, appearance of anew technology, or the like. In addition, some of the terms mentioned inthe description of the present invention have been selected by theapplicant at his or her discretion, the detailed meanings of which aredescribed in relevant parts of the description herein. Furthermore, itis required that the present invention is understood, not simply by theactual terms used but by the meanings of each term lying within.

In the specification, the term ‘signaling’ refers totransmission/reception of service information (ST) provided in abroadcast system, an Internet broadcast system, and/or abroadcast/Internet fusion system. The SI includes broadcast serviceinformation (e.g., ATSC-SI and/or DVB-SI) provided in each currentlyexisting broadcast system.

In the specification, the term ‘broadcast signal’ is defined asincluding signals and/or data provided in bidirectional broadcastingsuch as Internet broadcasting, broadband broadcasting, communicationbroadcasting, data broadcasting, and/or video on demand (VOD) as well asterrestrial broadcasting, cable broadcasting, satellite broadcasting,and/or mobile broadcasting.

In the specification, the term ‘physical layer pipe (PLP)’ refers to apredetermined unit for transmitting data belonging to a physical layer.Accordingly, in the specification, the term ‘PLP’ may be replaced with a‘data unit’ or a ‘data pipe’.

One of important applications to be used in a digital broadcast (DTV)service may be a hybrid broadcast service based on connection between abroadcast network and an Internet network. The hybrid broadcast servicemay transmit enhancement data broadcast audio/video (A/V) contenttransmitted through a terrestrial broadcasting network or some of theA/V content in realtime through the Internet so as to allow users toexperience various contents.

The present invention proposes a method for encapsulating an IP packetand a MPEG-2 TS packet and a packet to be used in other broadcastsystems so as to be transmitted to a physical layer in a next-generationdigital broadcast system. In addition, the present invention alsoproposes a method for transmitting layer 2 signaling in the same headerformat.

The description below may be embodied in a device. For example, thedescription below may be performed by, for example, a signalingprocessor, a protocol processor, a processor, and/or a packet generator.

The present invention provides a method and apparatus for transmittingand receiving a broadcast signal for a next-generation broadcastservice. A next-generation broadcast service according to to anembodiment of the present invention is interpreted as including aterrestrial broadcasting service, a mobile broadcasting service, anultra high definition television (UHDTV) service, and the like.According to an embodiment of the present invention, a broadcast signalfor the aforementioned next-generation broadcast service may be processa broadcast signal using a non-multi input multi output (MIMO) method ora MIMO method. A non-MIMO method according to an embodiment of thepresent invention may include a multi input single output (MISO) method,a single input single output (SISO) method, and the like.

Hereinafter, for convenience of description, an example in which amultiple antenna of MISO or MIMO is two antennas, but the description ofthe present invention may be applied to a system using two or moreantennas.

FIG. 1 is a diagram illustrating a protocol stack for a hybrid-basednext-generation broadcast system according to an embodiment of thepresent invention.

The present invention proposes a structure of a data link(encapsulation) portion illustrated in FIG. 1 and proposes a method fortransferring a MPEG-2 transport stream (TS) and/or an Internet protocol(IP) packet transmitted from an upper layer to a physical layer. Inaddition, the present invention proposes a method for transmittingsignaling required for an operation of a physical layer and establishesa base for transmitting a new packet type to a physical layer when ahigher layer considers the new packet type for future use.

A corresponding protocol layer may also be referred to as various termssuch as a data link layer, an encapsulation layer, layer 2, and thelike. In the present invention, the protocol layer is referred to as alink layer. In actual application to the present invention, the protocollayer may be substituted with the term ‘link layer’ or a correspondinglayer may also be referred to as a new term.

A broadcast system according to the present invention may correspond toa hybrid broadcast system obtained by combining an IP centric broadcastnetwork and a broadband.

The broadcast system according to the present invention may be designedto maintain compatibility with a conventional MPEG-2-based broadcastsystem.

The broadcast system according to the present invention may correspondto a hybrid broadcast system based on combination of an IP centricbroadcast network, a broadband network, and/or mobile communicationnetwork or a cellular network.

Referring to FIG. 1, a physical layer may use a physical protocolemployed by a broadcast system such as an ATSC system and/or a DVBsystem.

An encapsulation layer may acquire IP datagram from information acquiredfrom the physical layer or convert the acquired IP datagram into aspecific frame (e.g., RS Frame, GSE-lit e, GSE, or signal frame). Here,the frame may include a set such as IP datagrams.

A fast access channel (FAC) may include information (e.g., mappinginformation between service ID and frame) for access to a service and/orcontent.

The broadcast system according to the present invention may use aprotocol such as an internet protocol (IP), a user datagram protocol(UDP), a transmission control protocol (TCP), asynchronous layeredcoding/layered coding transport (ALC/LCT), rate control protocol/RTPcontrol protocol (RCP/RTCP), hypertext transfer protocol (HTTP), andfile delivery over unidirectional transport (FLUTE). A stack betweenthese protocols may be understood with reference to the structureillustrated in FIG. 1.

In the broadcast system according to the present invention, data may betransmitted in the form of ISO base media file format (ISOBMFF).Electrical service guide (ESG), non real time (NRT), audio/video (A/V),and/or general data may be transmitted in the form of ISOBMFF.

Transmission of data through a broadcast network may includetransmission of linear content and/or transmission of non-linearcontent.

Transmission of RTP/RTCP-based A/V, and data (closed caption, emergencyalert message, etc.) may correspond to transmission of linear content.

A RTP payload may be transmitted to be encapsulated in the form ofRTP/AV stream and/or ISO based media file format including a networkabstraction layer (NAL). Transmission of the RTP payload may correspondto transmission of linear content. Transmission in the form ofencapsulation of ISO based media file format may include a MPEG DASHmedia segment for A/V, etc.

Transmission of FLUTE-ESG, transmission of non-timed data, andtransmission of NRT content may correspond to transmission of non-linearcontent. These may be transmitted to be encapsulated in the form of aMIME type file and/or ISO based media file format. Transmission in theform of encapsulation of ISO based media file format may include a MPEGDASH media segment for A/V, etc.

Transmission of a broadcast network may be separately considered astransmission of content and transmission of signaling data.

Transmission of content may include transmission of linear content (A/Vand data (closed caption, emergency alert message, etc.), transmissionof non-linear content (ESG, non-timed data, etc.), and transmission ofMPEG DASH-based media segment (A/V and data).

Transmission of signaling data may include transmission containing asignaling table (which includes MPD of MPEG DASH) transmitted in abroadcast network.

The broadcast system according to the present invention may supportsynchronization between linear/non-linear contents transmitted through abroadcast network or synchronization between content transmitted througha broadcast network and content transmitted through a broadband. Forexample, when one UD content item is segmented and simultaneouslytransmitted in a broadcast network and a broadband, a receiver mayadjust a timeline dependent upon a transmission protocol and synchronizecontent of a broadcast network and content of a broadband to reconfigureone UD content item.

An application layer of the broadcast system according to the presentinvention may embody technological characteristics of interactivity,personalization, second screen, and automatic content recognition (ACR).These characteristics may be important to extension to ATSC3.0 fromATSC2.0 as North America broadcast standard. For example, forcharacteristics of interactivity, HTML5 may be used.

A presentation of the broadcast system according to the presentinvention may use HTML and/or HTML5 in order to identify a spatial andtemporal relationship between components or interactive applications.

A broadcast system according to another embodiment of the presentinvention may be formed by adding some features to the aforementionedbroadcast system or modifying some feature of the aforementionedbroadcast system, and thus the description of components may besubstituted with the above description of the aforementioned broadcastsystem.

A broadcast system according to another embodiment of the presentinvention may include a system structure that maintains compatibilitywith an MPEG-2 system. For example, linear/non-linear contenttransmitted by a conventional MPEG-2 system may be supported to bereceived and operated in an ATSC 3.0 system or processing of A/V anddata may be flexibly adjusted according to data received in the ATSC 3.0system, that is, whether the data is MPEG-2 TS or IP datagram.

An encapsulation layer of the broadcast system according to anotherembodiment of the present invention may convert information/dataacquired from a physical layer into MPEG-2 TS or IP datagram or convertthe information/data into a specific frame (e.g., RS Frame, GSE-lite,GSE, or signal frame) using IP datagram.

The broadcast system according to another embodiment of the presentinvention may include signaling information that can be flexiblyacquired according to whether data received in the ATSC 3.0 system isMPEG-2 TS or IP datagram in order to acquire services/content through abroadcast network. That is, the broadcast system may acquire signalinginformation based on MPEG-2 TS or acquire signaling information fromdata according to a UDP protocol.

The broadcast system according to the present invention may supportsynchronization between broadcast-based linear/non-linear contentsencapsulated in the form of MPEG-2 TS and/or IP datagram. In addition,the broadcast system may support synchronization between contentfragments transmitted through a broadcast network and a broadband. Forexample, when one UD content item is segmented and is simultaneouslytransmitted through a broadcast network and a broadband, a receiver mayadjust timeline dependent upon a transmission protocol and synchronizecontent of a broadcast network and content of a broadband to reconfigureone UD content item.

FIG. 2 is a diagram illustrating an interface of a link layer accordingto an embodiment of the present invention.

The case in which an IP packet and/or a MPEG-2 TS packet that aremaintain used in digital broadcasting are input to a transmitter may beconsidered. The transmitter can also support a structure of a packet ofa new protocol that can be used in next-generation broadcasting forfuture use. Data and singling that are encapsulated in a link layer maybe transmitted to a physical layer. The transmitter may performprocessing appropriate for a protocol of a physical layer supported by abroadcast system on the transmitted data (including signaling data) totransmit a signal including the corresponding data.

A receiver may restore data and signaling transmitted from the physicallayer in the form of data that can be processed in a higher layer. Thereceiver may differentiate whether a packet transmitted from thephysical layer is signaling (or signaling data) or data (or contentdata) by reading a header of a packet or via other methods to bedescribed later.

Signaling (i.e., signaling data) transmitted from a link layer of atransmitter may include signaling that is transmitted from an upperlayer and needs to be transmitted to an upper layer of a receiver,signaling that is generated in a link layer and provides information ondata processing in a link layer of a receiver, and/or signaling that isgenerated in an upper layer or a link layer but is transmitted for rapiddetection of specific data (e.g., service, content, and/or signalingdata) in a physical layer.

FIG. 3 is a diagram illustrating a structure of a packet of a link layeraccording to an embodiment of the present invention.

According to an embodiment of the present invention, the packet of thelink layer may include a fixed header, an extended header, and/or apayload.

The fixed header may be a header with a fixed size. For example, thefixed header may have a size of 1 byte. The extended header may be aheader with a changeable size. The payload containing data transmittedby a higher layer may be positioned behind the fixed header and theextended header.

The fixed header may include a packet type element and/or an indicatorpart element.

The packet type element may have a size of 3 bits. The packet typeelement may identify a packet type of a higher layer (a higher layer ofa link layer). A packet type identified according to a value of a packettype element will be described later.

The indicator part element may include a method for configuring apayload and/or information for configuring an extended header. Theconfiguring method and/or configuring information indicated by theindicator part element may be changed according to a packet type.

FIG. 4 is a diagram illustrating a packet type according to a packettype element according to an embodiment of the present invention.

For example, when a value of a packet type element is ‘000’, the valuemay indicate that a packet transmitted to a link layer from a higherlayer is a packet of a Internet protocol version 4 (IPv4).

When a value of a packet type element is ‘001’, the value may indicatethat a packet transmitted to a link layer form a higher layer is apacket of an Internet protocol version 6 (IPv6).

When a value of a packet type element is ‘010’, the value may indicatethat a packet transmitted to a link layer from a higher layer is anencapsulated IP packet.

When a value of a packet type element is ‘011’, the value may indicatethat a packet transmitted to a link layer from a higher layer is apacket of MPEG-2 TS.

When a value of a packet type element is ‘101’, the value may indicatethat a packet transmitted to a link layer from a higher layer is apacket of a packetized stream. For example, the packetized stream maycorrespond to a MPEG media transport packet.

When a value of a packet type element is ‘110’, the value may indicatethat a packet transmitted to a link layer from a higher layer is apacket for transmitting signaling (signaling data).

When a value of a packet type element is ‘11’, the value may indicatethat a packet transmitted to a link layer from a higher layer is a framepacket type.

FIG. 5 is a diagram illustrating a structure of a header of a link layerwhen an IP packet is transmitted to a link layer, according to anembodiment of the present invention.

When the IP packet is input to a link layer, a value of a packet typeelement may be 000B (3 bits of 000) or 001B (3 bits of 001).

When the IP packet is input, an indicator part element subsequent to apacket type element may include a concatenation/segmentation (C/S) fieldand/or an additional field of 3 bits (hereinafter, referred to as an‘additional field’) with reference to the header of the packet of thelink layer.

With regard to the packet of the link layer, an additional field of thefixed header and information of the extended header may be determinedaccording to 2 bits of a concatenation/segmentation (C/S) fieldsubsequent to the packet type element.

The C/S field may indicate the form in which an input IP packet isprocessed and include information about a length of an extended headeraccording thereto.

According to an embodiment of the present invention, when a value of aC/S field is 00B (2 bits of 00), the value corresponds to the case inwhich a payload of a link layer packet includes a normal packet. Thenormal packet may refer to the case in which an input IP packet is apayload of the link layer packet without changes. In this case, anadditional field of a fixed header part may not be used and may bereserved for future use. In this case, an extended header may not beused.

When a value of a C/S field is 01B (2 bits of 01), the value maycorrespond to the case in which a payload of a link layer packetincludes a concatenated packet. The concatenated packet may include oneor more IP packets. That is, one or more IP packets may be included inthe payload of the link layer packet. In this case, the extended headermay not be used, and an additional field subsequent to the C/S field maybe used as a count field. The count field will be described in detail.

When a value of a C/S field is 10B (2 bits of 10), the value maycorrespond to the case in which a payload includes a segmented packet.The segmented packet may be a packet including one segmented by dividingone IP packet into several segments. That is, the payload of the linklayer packet may include any one of a plurality of segments included inan IP packet. An additional field subsequent to the C/S field may beused as a segment ID. The segment ID may be information about foruniquely identifying a segment. The segment ID may be an ID denoted whenan IP packet is segmented and may indicate that segments that aretransmitted for future use are components of the same IP packet when thesegments are combined. The segment ID may have a size of 3 bits and maysimultaneously support segmentation of 8 IP packets. For example,segments segmented from one IP packet may have the same segment ID. Inthis case, the extended header may have a length of 1 byte. In thiscase, the extended header may include a segment sequence number (Seg_SN)field and a segment sequence number field, and/or a segment length(Seg_Len_ID) field.

A segment sequence number (Seg_SN) field may have a length of 4 bits andindicate a sequence number of a corresponding segment in an IP packet.When the IP packet of the Seg_SN field is segmented, the Seg_SN fieldmay be a field used to check a sequence of each segment. Accordingly,link layer packets including a payload segmented from one IP packet mayhave the same segment ID (Seg_ID) but have different values of a Seg_SNfield. The Seg_SN field may have a size of 4 bits, and in this case, oneIP packet can be segmented up to 16 segments. In order to segment an IPpacket into more segments, a size of a Seg_SN field may be extended andmay indicate a sequence and/or number of a segment.

A segment length ID (Seg_Len_ID) field may have a length of 4 bits andmay be an ID for identifying a length of a segment. An actual length ofa segment according to a value of the Seg_Len_ID field may be identifiedaccording to a table to be described later. When an actual length valueof a segment instead of the Seg_Len_ID field is signaled, the Seg_Len_IDfield of 4 bits may be extended to a segment length field of 12 bits,and in this case, an extended header of 2 bits may be included in a linklayer packet.

A value of a C/S field is 11B (2 bits of 11), the value may correspondto the case in which a payload includes a segmented packet like in thecase in which a value of the C/S field is 10B. However, the value mayindicate that a segment (of a last sequence) positioned last amongsegments segmented from one IP packet is included in a payload. Areceiver may identify a link layer packet for transmitting a lastsegment and recognize a segment included in a payload of a correspondingpacket as a last segment of an IP packet using a value of the C/S fieldduring reconfiguration of one IP packet by collecting segments. Anadditional field subsequent to the C/S field may be used as a segmentID. In this case, the extended header may have a length of 2 bytes. Theextended header may include a segment sequence number (Seg_SN) fieldand/or a last segment length (L_Seg_Len) field.

A last segment length (L_Seg_Len) field may indicate an actual length ofa last segment. When an IP packet is segmented into the same size from afront part using the Seg_Len_ID field, a last segment may have adifferent size from other previous segments. Accordingly, a length of asegment may be directly indicated using the L_Seg_Len field. The lengthmay be different according to an allocated bit number of the L_Seg_Lenfield, but according to allocation of a bit number according to anembodiment of the present invention, the L_Seg_Len field may indicatethat a length of a last segment is 1 to 4095 bytes.

That is, when one IP packet is segmented into a plurality of segments,the IP packet may be segmented into segments with a predeterminedlength, but a length of the last segment may be changed according to thelength of the IP packet. Accordingly, it may be necessary to separatelysignal a length of a last segment. A description of a field with thesame name is substituted with the above description.

FIG. 6 is a diagram illustrating meaning of a C/S field andconfiguration information of a header according to an embodiment of thepresent invention.

When a value of the C/S field is 00, the value may indicate that anormal packet is included in a payload of a link layer packet and anadditional field is reserved. The extended header may not be included inthe link layer packet. In this case, a total length of a header of thelink layer packet may be 1 byte.

When a value of the C/S field is 01, the concatenated packet may beincluded in a payload of a link layer packet and an additional field maybe used as a count field. The count field will be described later. Theextended header may not be included in a link layer packet. In thiscase, a total length of a header of the link layer packet may be 1 byte.

When a value of the C/S field is 10, the segmented packet may beincluded in a payload of a link layer packet and an additional field maybe used as a segment ID. The extended header may be included in the linklayer packet. The extended header may include a Seg_SN field and/or aSeg_Len_ID field. A description of the Seg_SN field or the Seg_Len_IDfield may be substituted with the above or following description. Atotal length of the header of the link layer packet may be 2 bytes.

When a value of the C/S field is 11, a segmented packet (a packetincluding a last segment) may be included in a payload of a link layerpacket and an additional field may be used as a segment ID. The extendedheader may be included in a link layer packet. The extended header mayinclude a Seg_SN field and/or an L_Seg_Len field. A description of theSeg_SN field or the L_Seg_Len field is substituted with the above orfollowing description. A total length of a header of a link layer packetmay be 3 bytes.

FIG. 7 is a diagram illustrating meaning according to a value of a countfield according to an embodiment of the present invention.

A count field may be used when a payload of a link layer packet includesa concatenated packet. The count field may indicate the number of IPpackets included in one payload. A value of the count field may indicatethe number of IP packets that are concatenated without changes, but 0 orone concatenation is meaningless, and thus the count field may indicatethat an IP packet with the number obtained by adding 2 to the value ofthe count field is included in a payload. According to an embodiment ofthe present invention, 3 bits are allocated to the count field, and thusthis may indicate that a maximum of 9 IP packets are included in apayload of one link layer packet. When more IP packets need to beincluded in one payload, a length of the count field may be extended or9 or more IP packets may be further signaled in the extended header.

FIG. 8 is a diagram illustrating the meaning and segment lengthaccording to a value of a Seg_Len_ID field according to an embodiment ofthe present invention.

The Seg_Len_ID field may be used to represent a length of a segmentexcept for a last segment among a plurality of segments. In order toreduce overhead of a header that is required to represent the length ofa segment, the size of a segment may be limited to 16.

A length of a segment may be determined according to an input size of apacket determined according to a code rate of forward error correction(FEC) processed by a physical layer and may be determined as each valueof the Seg_Len_ID field. For example, with respect to each value of theSeg_Len_ID field, a length of a segment may be predetermined. In thiscase, information about a length of a segment according to each value ofthe Seg_Len_ID field may be generated by a transmitter and transmittedto a receiver, and the receiver may store the information. A length of asegment set according to each value of the Seg_Len_ID field may bechanged, and in this case, the transmitter may generate new informationabout the length of the segment and transmit the information to thereceiver, and the receiver may update stored in formation based on theinformation.

When processing of a physical layer is operated irrespective of thelength of the segment, the length of the segment may be acquired asshown in the illustrated equation.

Here, a length unit (Len_Unit) may be a basic unit indicating a segmentlength and min_Len may be a minimum value of a segment length. Len_Unitand min_Len need to be the same in the transmitter and the receiver, andit may be effective that Len_Unit and min_Len are not changed afterbeing changed once. The values may be determined in consideration ofprocessing capability of FEC of a physical layer in an initializationprocedure of a system. For example, as illustrated, the values mayindicate a length of a segment that is represented according to thevalue of the Seg_Len_ID field, and in this case, a value of Len_Unit maybe 256 and a value of min_Len may be 512.

FIG. 9 is a diagram illustrating a procedure of encapsulating a normalpacket and an equation of a length of a link layer packet according toan embodiment of the present invention.

As described above, when an input IP packet is within a processing rangeof a physical layer and is concatenated or is not segmented, the inputIP packet may be encapsulated as a normal packet. The followingdescription may be applied to an IP packet of IPv4 or IPv6 in the sameway. One IP packet may be a payload of a link layer packet withoutchanges, and a value of a packet type element may be 000B (IPv4) or 001B(IPv6), and a value of the C/S field may be 00B (normal packet). Theremaining 3 bits of a fixed header may be set as a reserved field forother future use.

The length of the link layer packet may be identified as follows. Theheader of the IP packet may include a field indicating a length of an IPpacket. A field indicating a length is positioned at the same position,and thus the receiver may check a field at a position spaced apart froman initial point (a start point) of a link layer packet by apredetermined offset so as to recognize the length of a payload of alink layer packet. The receiver may read a length field with a length of2 bytes from a position spaced apart from a start point of a payload by2 bytes in the case of IPv4 and from a position spaced apart from astart point of a payload by 4 bytes in the case of IPv6.

Referring to the illustrated equation, when a value of a length field ofIPv4 is LIPv4, LIPv4 indicates a total length of IPv4, and thus anentire length of the link layer packet may be obtained by adding aheader length LH (1 byte) of the link layer packet to the LIPv4. Here,LT indicates a length of the link layer packet.

Referring to the illustrated equation, when a value of a length field ofIPv6 is LIPv6, LIPv6 indicates only a length of a payload of an IPpacket of IPv6, and thus a length of a link layer packet may be obtainedby adding a length of a header of a link layer packet and a length (40bytes) of a fixed header of IPv6. Here, LT may refer to a length of alink layer packet.

FIG. 10 is a diagram illustrating a procedure for encapsulating aconcatenated packet and an equation of a length of a link layer packetaccording to an embodiment of the present invention.

When an input IP packet cannot reach a range of processing of a physicallayer, several IP packets may be concatenated to encapsulate one linklayer packet. The following description may be applied to an IP packetof IPv4 or IPv6 in the same way.

Several IP packets may be a payload of a link layer packet, a value ofthe packet type element may be 000B (IPv4) or 001B (IPv6), and a valueof a C/S field may be 01B (concatenated packet). A 3-bit count fieldindicating the number of IP packets included in one payload may besubsequent to the C/S field.

In order to obtain a length of a concatenated packet, the receiver mayuse a similar method to in the case of a normal packet. When the numberof concatenated IP packets indicated by a count field is n, a length ofa header of a link layer packet is LH, and a length of each IP packet isLk (here, 1≤k≤n), an entire length LT of the link layer packet may becalculated as shown in the illustrated equation.

Here, a concatenated packet has only information about a fixed header,and thus LH=1 (byte), and each Lk (1≤k≤n) value may be checked byreading a value of a length field present in a header of each IP packetincluded in the concatenated packet. The receiver may parse a lengthfield of a first IP packet at a point with a predetermined offset from apoint in which a header of a link layer packet ends and a payload isstarted and identify a length of the first IP packet using the lengthfield. The receiver may parse a length field of a second IP packet at apoint with a predetermined offset from a point in which the length ofthe first IP packet ends and identify the length of the second IP packetusing the length field. The above method may be repeated by as much asthe number of IP packets included in the payload of the link layerpacket so as to identify the length of the payload of the link layerpacket.

FIG. 11 is a diagram illustrating a procedure for obtaining a length ofa concatenated packet including an IPv4 packet and an equation forcalculating an offset value at which a length field of an IP packet ispositioned according to an embodiment of the present invention.

When an IP packet is input to a transmitter, it is not difficult to reada length field of an IP packet by the transmitter, but a receiver canknow only the number of IP packets included in a link layer packetthrough a header, and thus a position of each length field may not beknown. However, a length field is always positioned at the same positionin a header of the IP packet, and thus the position of the length fieldmay be retrieved so as to obtain a length of each IP packet included ina payload of a concatenated packet using the following method.

When n IP packets included in the payload of the concatenated packet areIP1, IP2, . . . , IPk, . . . , IPn, respectively, a length fieldcorresponding to IPk may be positioned to be spaced apart from a startpoint of the payload of the concatenated packet by Pk bytes. Here, Pk(1≤k≤n) may be an offset value in which the length field of a k^(th) IPpacket is positioned from the start point of the payload of theconcatenated packet and may be calculated according to the shownequation.

Here, P1 of a packet of IPv4 may be 2 bytes. Accordingly, while P1 to Pkare sequentially updated, Lk corresponding thereto may be read andapplied to the aforementioned equation of FIG. 10 so as to finallyacquire a length of a concatenated packet.

FIG. 12 is a diagram illustrating a procedure for calculating a lengthof a concatenated packet including an IPv6 packet and an equation forcalculating an offset value in which a length field of an IP packet ispositioned, according to an embodiment of the present invention.

When the IPv6 packet is included in a payload of a link layer packet ina concatenated form, a procedure for obtaining a length of the payloadwill now be described. A length field contained in the IPv6 packet islength information about the payload of the IPv6 packet, and thus 40bytes as a length of a fixed header of IPv6 may be added to the lengthof the payload of the IPv6 packet, indicated by the length field, toacquire the length of the IPv6 packet.

When n IP packets included in the payload of the concatenated packet areIP1, IP2, . . . , IPk, . . . , IPn, respectively, a length fieldcorresponding to IPk may be positioned to be spaced apart from a startpoint of the payload of the concatenated packet by Pk bytes. Here, Pk(1≤k≤n) may be an offset value in which the length field of a k^(th) IPpacket is positioned from the start point of the payload of theconcatenated packet and may be calculated according to the shownequation. Here, in the case of IPv6, P1 may be 4 bytes. Accordingly,while P1 to Pk are sequentially updated, Lk corresponding thereto may beread and applied to the aforementioned equation of FIG. 10 so as tofinally acquire a length of a concatenated packet.

FIG. 13 is a diagram illustrating a procedure for encapsulating asegmented packet according to an embodiment of the present invention.

The following description may be applied to an IP packet of IPv4 or IPv6in the same way. One IP packet may be segmented to payload of aplurality of link layer packets, a value of a packet type element may be000B (IPv4) or 001B (IPv6), and a value of the C/S field may be 10B or11B according to a configuration of a segment.

With regard to the C/S field, a C/S field value may be 11B only in asegment corresponding to a very last part of the IP packet and may be10B in the all remaining segments. As described above, a value of theC/S field may indicate information about an extended header of a linklayer packet. That is, when a value of the C/S field is 10B, the C/Sfield may have a header with a length of 2 bytes, and when a value ofthe C/S field is 11 B, the C/S field may have a header with a length of3 bytes.

In order to indicate that link layer packets are segmented from the sameIP packet, segment ID (Seg_ID) values included in headers of therespective link layer packets need to have the same value. In order toindicate sequence information of segments for recombination of a normalIP packet by a receiver, a Seg_SN value that is sequentially increasedmay be recorded in the headers of the respective link layer packets.

When an IP packet is segmented, a length of a segment may be determinedand segmented may be performed with the same length, as described above.Then a Seg_Len_ID value corresponding to the corresponding lengthinformation may be recorded in a header. In this case, a length of alastly positioned segment may be changed compared with a previoussegment, and thus length information may be directly indicated using anL_Seg_Len field.

Length information indicated using a Seg_Len_ID field and a L_Seg_Lenfield may indicate only information about a segment, that is, a payloadof a link layer packet, and thus the receiver may identify total lengthinformation of link layer packets by adding a header length of a linklayer packet to a payload length of the link layer packet with referenceto the C/S field.

FIG. 14 is a diagram illustrating a procedure for segmenting an IPpacket and header information of a link layer packet according to themethod, according to an embodiment of the present invention.

The diagram also illustrates a field value of a header of each linklayer packet while the IP packet is segmented to be encapsulated as linklayer packets.

For example, an IP packet of a length of 5500 bytes may be input to alink layer in an IP layer, the IP packet may be five segments S1, S2,S3, S4, and S5, and headers H1, H2, H3, H4, and H5 may be added to thesegments SI, S2, S3, S4, and S5 to be encapsulated as respective linklayer packets.

In the case of an IPv4 packet, a value of a packet type element may bedetermined as 000B. A C/S field value of H1 to H4 may be 10B and a C/Sfield value of H5 may be 11B. All segment IDs (Seg_IDs) indicating thesame IP packet configuration may be 000B and Seg_SN fields maysequentially indicate 0000B to 0100B in H1 to H5.

Since a value obtained by dividing 5500 bytes by 5 is 1100 bytes, when asegment with a length of 1024 bytes closest to 1100 bytes is configured,a length of S5 as a last segment may be 1404 bytes (01010111100B). Inthis case, a Seg_Len_ID field may have a value of 0010B in theaforementioned example.

FIG. 15 is a diagram illustrating a procedure for segmenting an IPpacket including cyclic redundancy check (CRC) according to anembodiment of the present invention.

When an IP packet is segmented and transmitted to a receiver, atransmitter may attach CRC behind the IP packet such that the receiverchecks integrity of combined packets. In general, the CRC may beattached to a last packet, and thus the CRC may be included in the lastsegment after a segmentation procedure.

When the receiver receives data that exceeds a length of the lastsegment, the receiver may recognize the data as CRC. In addition, thereceiver may signal a length containing a length of the CRC as a lengthof the last segment.

FIG. 16 is a diagram illustrating a header structure of a link layerpacket when an MPEG-2 transport stream (TS) is input to a link layer,according to an embodiment of the present invention.

A packet type element may identify that an MPEG-2 TS packet is input toa link layer. For example, in this case, a value of the packet typeelement may be 011B.

The diagram illustrates a header structure of a link layer packet whenthe MPEG-2 TS is input. When the MPEG-2 TS packet is input to the linklayer, a header of the link layer packet may include a packet typeelement, a count field, a PID indicator (P1) field, and/or a deletednull packet indicator (DI) field.

For example, a count field of 2 bits or 3 bits, a PID indicator (PI)field of 1 bit, and a deleted null packet indicator (DI) of 1 bit may besubsequent to a packet type element of a header of a link layer packet.When 2 bits are used as a count field, the remaining 1 bit may bereserved as a reserved field for other future use. According toapposition of the reserved field, a fixed header part may be configuredwith various structures as illustrated in FIGS. 16(a) to 16(d). Althoughthe present invention is described in terms of a header illustrated inFIG. 16(a), the same description may also be applied to other types ofheaders.

When a MPEG-2 TS packet is input to a link layer, an extended header maynot be used in packet type=011.

A count field may identify the number of MPEG-2 TS packets contained ina payload of a link layer packet. A size of one MPEG-2 TS packet is verysmall compared with an input size of low-density parity-check (LDPC) asan FEC scheme that is likely to be employed in a physical layer of anext-generation broadcasting system, and thus concatenation of MPEG-2 TSpackets in a link layer may be basically considered. That is, one ormore MPEG-2 TS packets may be contained in a payload of a link layerpacket. However, the number of concatenated MPEG-2 TS packets may belimited to be identified as 2 bits or 3 bits. A length of a MPEG-2 TSpacket has a predetermined size (e.g., 188 bytes), and thus a receivercan also infer a size of a payload of a link layer packet using a countfield. An example for determining the number of MPEG-2 TS packetsaccording to a count field value will be described later.

A common PID indicator (PI) field may be set to 1 when packetidentifiers (PIDs) of MPEG-2 TS packets contained in a payload of onelink layer packet are the same, and otherwise, the common PI field maybe set to 0. The common PI field may have a 1 bit size.

A null packet deletion indicator (DI) field may be set to 1 when a nullpacket contained and transmitted in a MPEG-2 TS packet is deleted, andotherwise, the null packet DI may be set to 0. The null packet DI fieldmay have a size of 1 bit. When a DI field is 1, the receiver may reusesome fields of the MPEG-2 TS packet in order to support null packetdeletion in a link layer.

FIG. 17 is a diagram illustrating the number of MPEG-2 TS packetsincluded in a payload of a link layer packet according to a value of acount field, according to an embodiment of the present invention.

When the count field is 2 btis, there may be 4 numbers of cases withrespect to the number of concatenated MPEG-2 TS packets. The size of thepayload of the link layer packet except for a sync byte (47H) may alsobe identified by the count field.

The number of MPEG-2 TS packets allocated according to the number ofcount fields may be changed according to a system designer.

FIG. 18 is a diagram illustrating a header of an MPEG-2 TS packetaccording to an embodiment of the present invention.

The header of the MPEG-2 TS packet may include a sync byte field, atransport error indicator field, a payload unit start indicator field, atransport priority field, a PID field, a transport scrambling controlfield, an adaptation field control field, and/or a continuity counterfield.

The sync byte field may be used for packet synchronization and excludedduring encapsulation in a link layer. A transport error indicator (EI)positioned immediately after the sync byte field may not be used by atransmitter, and when an unrestorable error occurs in the receiver, thetransport EI may be used to indicate the error to a higher layer. Due tothis purpose, the transport EI field may be a bit that is not used bythe transmitter.

When error cannot be corrected in a stream, the transport EI field maybe field that is set during a demodulation process and indicates thatthere is error that cannot be corrected in a packet.

The payload unit start indicator field may identify whether a packetizedelementary stream (PES) or program-specific information (PSI) isstarted.

The transport priority field may identify whether a packet has higherpriority than other packets having the same PID.

The PID field may identify a packet.

The transport scrambling control field may identify whether a scrambleis used and/or whether a scramble is used using an odd numbered key oran even numbered key.

The adaptation field control field may identify whether an adaptationfield is present.

The continuity counter field may indicate a sequence number of a payloadpacket.

FIG. 19 is a diagram illustrating a procedure for changing use of atransport EI field by a transmitter according to an embodiment of thepresent invention.

As illustrated, when a DI field is 1, a transport error indicator fieldmay be changed to use of a deletion point indicator (DPI) field in alink layer of the transmitter.

The DPI field may be restored to the transport error indicator fieldafter a null packet related processing is completed in the link layer ofthe receiver. That is, the DI field may be a field that simultaneouslyindicates whether use of the transport error indicator field is changedas well as whether a null packet is deleted.

FIG. 20 is a diagram illustrating a procedure for encapsulating anMPEG-2 TS packet according to an embodiment of the present invention.

Basically, the MPEG-2 TS packet is concatenated, and thus a payload ofone link layer packet may include a plurality of MPEG-2 TS packets, andthe number of the MPEG-2 TS packets may be determined according to theaforementioned method. When the number of MPEG-2 TS packets included ina payload of one link layer packet is n, each MPEG-2 TS packet may berepresented by Mk (1≤k≤n).

The MPEG-2 TS packet may include a fixed header of 4 bytes and a payloadof 184 bytes in general. 1 byte of a header of 4 bytes may be the syncbyte that has the same value 47H. Accordingly, one MPEG-2 TS packet ‘Mk’may include a sync part S of 1 byte, a fixed header part Hk of 3 bytesexcept for sync byte, and/or a payload part Pk of 184 bytes (here,1≤k≤n).

When the adaptation field is used in a header of the MPEG-2 TS packet,the fixed header part may be included in a portion immediately in frontof the adaptation field and the payload part may be included in theremaining adaptation part.

When n input MPEG-2 TS packets are [M1, M2, M3, . . . , Mn], the inputMPEG-2 TS packets may have arrangement of [S, H1, PI, S, H2, P2, . . . ,S, Hn, Pn]. The sync part may always have the same value, and in thisregard, even if the transmitter does not transmit the sync part, thereceiver may find a corresponding position in the receiver and re-insertthe sync part into the corresponding position. Accordingly, when apayload of a link layer packet is configured, the synch part may beexcluded to reduce the size of a packet. When a combination of an MPEG-2TS packet having the arrangement is configured with a payload of a linklayer packet, a header part and a payload part may be segmented with[H1, H2, . . . , Hn, P1, P2, . . . , Pn].

When a PI field value is 0, and a DI field value is 0, a length of apayload of a link layer packet is (n×3)+(n×184) bytes, and when 1 byteof a header length of the link layer packet is added, a total link layerpacket length may be obtained. That is, the receiver may identify alength of a link layer packet through this procedure.

FIG. 21 is a diagram illustrating a procedure for encapsulating MPEG-2TS packets having the same PIDs, according to an embodiment of thepresent invention.

When broadcasting data is continuously streamed, PID values of MPEG-2TSs included in one link layer packet may be the same. In this case,repeated PID values may be simultaneously marked so as to reduce a sizeof a link layer packet. In this case, a PID indicator (PI) field in aheader of a link layer packet may be used.

A common PID indicator (PI) value of the header of the link layer packetmay be set to 1. As described above, in the payload of the link layerpacket, n input MPEG-2 TS packets [M1, M2, M3, . . . , Mn] may bearranged in [H1, H2, . . . , Hn, P1, P2, . . . , Pn] by excluding thesync part and segmenting a header part and a payload part. Here, thecase in which a header part [H1, H2, . . . , Hn] of the MPEG-2 TS hasthe same PID, and thus even if a PID is marked only once, the receivermay restore the PID to an original header. When a common PID is a commonPID (CPID) and a header obtained by excluding PID from a header Hk ofthe MPEG-2 TS packet is H′k (1≤k≤n), a header part [H, H2, . . . , Hn]of the MPEG-2 TS included in a payload of a link layer packet isreconfigured as [CPID, H′1, H′2, . . . , H′n]. This procedure may bereferred to as common PID reduction.

FIG. 22 is a diagram illustrating an equation for obtaining a length ofa link layer packet during a common PID reduction procedure and a commonPID reduction procedure, according to an embodiment of the presentinvention.

A header part of a MPEG-2 TS packet may include a PID with a size of 13bits. When MPEG-2 TS packets included in a payload of a link layerpacket have the same PID value, PIDs may be repeated by as much as thenumber of concatenated packets. Accordingly, a PID part may be excludedfrom a header part [H1, H2, . . . , Hn] of an original MPEG-2 TS packetto reconfigure [H′1, H′2, . . . , H′n], a value of the common PID may beset to a value of a common PID (CPID), and then the CIPD may bepositioned in front of the reconfigured header part.

The PID value may have a length of 13 bits, and a stuffing bit may beadded in order to form all packets in the form of a byte unit. Thestuffing bit may be positioned in front of or behind the CPID and may beappropriately arranged according to a configuration of otherconcatenated protocol layers or embodiments of a system.

In the case of encapsulation of MPEG-2 TS packets having the same PID,the PID may be excluded from the header part of the MPEG-2 TS packet andan encapsulation procedure is performed, and thus the length of apayload of a link layer packet may be obtained as follows.

As illustrated, a header of a MPEG-2 TS packet obtained by excluding thesync byte may have a length of 3 bytes, and when a PID part of 13 bitsmay be excluded from the header of the MPEG-2 TS packet, the header ofthe MPEG-2 TS packet may be 11 bits. Accordingly, when n packets areconcatenated, the packets have (n×11) bits, and when the number ofconcatenated packets is set to a multiple of 8, (n×11) bits may be alength of a byte unit. Here, a stuffing bit with a length of 3 bits maybe added to 13 bits as a common PID length to configure a CPID part witha length of 2 bytes.

Accordingly, in the case of a link layer packet formed by encapsulatingn MPEG-2 TS packets having the same PID, when a header length of a linklayer packet is LH, a length of a CPID part is LCPID, and a total lengthof a link layer packet is LT, LT may be obtained according to the shownequation.

In the embodiment illustrated in FIG. 21, LH may be 1 byte and LCPID maybe 2 bytes.

FIG. 23 is a diagram illustrating the number of concatenated MPEG-2 TSpackets according to a value of a count field and a length of a linklayer packet according to the number when common PID reduction isapplied, according to an embodiment of the present invention.

When the number of the concatenated MPEG-2 TS packets are determined, ifall packets have the same PID, the aforementioned common PID reductionprocedure may be applied, and the receiver may acquire a length of alink layer packet according to the equation described in relation to theprocedure.

FIG. 24 is a diagram illustrating a method for encapsulating an MPEG-2TS packet including a null packet, according to an embodiment of thepresent invention.

During transmission of the MPEG-2 TS packet, the null packet may beincluded in a transport stream for adjustment to a fixed transfer rate.The null packet is an overhead part in terms of transmission, and thuseven if a transmitter does not transmit the null packet, a receiver mayrestore the null packet. In order to delete and transmit the null packetby the transmitter and find and restore the number and position of thedeleted packets by the receiver, a null packet deletion indicator (DI)field in the header of the link layer packet may be used. In this case,a value of the null packet deletion indictor (DI) of the header of thelink layer packet may be set to 1.

Encapsulation when a null packet is positioned at an arbitrary pointbetween input transport streams may be performed by sequentiallyconcatenating n packets except for the null packet. The number ofcounted null packets that are continuously excluded may be contained ina payload of a link layer packet, and the receiver may generate and filla null packet in an original position based on the count value.

When n MPEG-2 TS packets except for the null packet is [M1, M2, M3, . .. , Mn], the null packet may be positioned at any position between M1 toMn. One link layer packet may include a counted number of null packetswith a number of times of 0 to n. That is, when a number of times thatnull packets are counted in one link layer packet is p, a range of p maybe 0 to n.

When a count value of null packets is Cm, a range of m may be 1≤m≤p, andwhen p=0, Cm is not present. As described above, MPEG-2 TS packetsbetween which Cm is positioned may be indicated using a field in aheader of the MPEG-2 TS packet, in which use of a transport errorindicator (EI) is changed to a deletion point indicator (DPI).

The present invention proposes a case in which Cm has a length of 1 byteand also considers a case in which Cm is extended when there is a marginfor a length of a packet for future use. Cm of I-byte length may count amaximum of 256 null packets. A field that functions as an indicator of anull packet is positioned in a header of a MPEG-2 TS packet, and thuscalculation may be performed by excluding null packets by as much as avalue obtained by adding 1 to a value indicated by Cm. For example, inthe case of Cm=0, one null packet may be excluded, and in the case ofCm=123, 124 null packets may be excluded. When continuous null packetsexceed 256, a 257^(th) null packet may be processed as a normal packet,and next null packets may be processed as null packets using theaforementioned method.

As illustrated, when null packets may be positioned between MPEG-2 TSpackets corresponding to Mi and Mi+1, a counted number of the nullpackets is C1, and when a null packet is positioned between MPEG-2 TSpackets corresponding to Mj and Mj+1, a counted number of the nullpackets is Cp, and in this case, an actual transmission sequence may be[ . . . , Mi, C1, Mi+1, . . . , Mj, Cp, Mj+1, . . . ].

In a procedure for segmenting and reordering a header part and a payloadpart of an MPEG-2 TS packet instead of a null packet in order toconfigure a payload of a link layer packet, a count value Cm (1≤m≤p) ofnull packets may be disposed between the header part and the payload ofthe MPEG-2 TS packet. That is, the payload of the link layer packet maybe disposed like [H1, H2, . . . . Hn, C1, . . . , Cp, P1, P2, . . . ,Pn], and a receiver may sequentially check a count value on abyte-by-byte basis at an order indicated in a DPI field of Hk andrestore a null packet at an original order of an MPEG-2 TS packet by asmuch as the count value.

FIG. 25 is a diagram illustrating a procedure for processing anindicator for counting deleted null packets and an equation forobtaining a length of a link layer packet during the procedure,according to an embodiment of the present invention.

A value of a DPI field may be set to indicate that null packets aredeleted and a count value of the deleted null packets is present. Asillustrated, when a value of a DPI field in Hi of a header of aplurality of MPEG-2 TS packets is 1, this may indicate that the MPEG-2TS packets are encapsulated by excluding an null packet between Hi andHi+1 and 1-byte count value according thereto is positioned between aheader part and a payload part.

During this procedure, a length of a link layer packet may be calculatedaccording to the shown equation. Accordingly, in the case of a linklayer packet obtained by encapsulating n MPEG-2 TS packets from which anull packet is excluded, when a header length of the link layer packetis LH, a length of a count value Cm (1≤m≤p) of a null packet is LCount,and a total length of the link layer packet is LT, LT may be acquiredaccording to the shown equation.

FIG. 26 is a diagram illustrating a procedure for encapsulating anMPEG-2 TS packet including a null packet, according to anotherembodiment of the present invention.

Another encapsulation method for excluding a null packet, a payload of alink layer packet may be configured. According to another embodiment ofthe present invention, in a procedure for segmenting and reordering aheader part and a payload part of a MPEG-2 TS packet in order toconfigure a payload of a link layer packet, a count value Cm (1≤m≤p) ofnull packets may be positioned in a header part and an order of the nullpackets may be maintained. That is, a header of each MPEG-2 TS mayinclude a count value of null packets at a point in which a header ends.Accordingly, upon reading a value of a DPI field contained in a headerof each MPEG-2 TS and determining that the null packets are deleted, thereceiver may read a count value contained in a last part of thecorresponding header, regenerate null packets by as much as thecorresponding count value, and contain the null packets in a stream.

FIG. 27 is a diagram illustrating a procedure for encapsulating MPEG-2TS packets including the same packet identifier (PID) in a streamincluding a null packet, according to an embodiment of the presentinvention.

According to an embodiment of the present invention, in a streamincluding null packets, a procedure for encapsulating MPEG-2 TS packetsincluding the same packet identifier (PID) may be performed by combininga procedure for encapsulating a link layer packet by excluding theaforementioned null packet and a procedure for encapsulating MPEG-2 TSpackets having the same PID as a link layer packet.

Since null packets are allocated separate PIDs indicating the respectivenull packet, when the null packet are contained in an actual transportstream, the null packets are not processed with the same PID. However,after a procedure for excluding a null packet is performed, since only acount value of null packets is contained in a payload of a link layerpacket, the remaining n MPEG-2 TS packets have the same PID, and thusthe null packets may be processed using the aforementioned method.

FIG. 28 is a diagram illustrating an equation for obtaining a length ofa link layer packet while MPEG-2 TS packets including the same packetidentifier (PID) are encapsulated in a stream including a null packet,according to an embodiment of the present invention.

While MPEG-2 TS packets including the same packet identifier (PID) areencapsulated in a stream including null packets, a length of a linklayer packet may be derived according to the equation of FIGS. 22 and/or25. This may be summarized to obtain the illustrated equation.

FIG. 29 is a diagram illustrating a configuration of a link layer packetfor signaling transmission, according to an embodiment of the presentinvention.

In order to transmit signaling information as well as information aboutupdate of IP header encapsulation information and broadcasting channelscan information prior to reception of an IP packet or an MPEG-2 TSpacket by a receiver, the present invention proposes a packet form fortransmitting signaling (e.g., signaling data) to a link layer.

According to an embodiment of the present invention, when a value of apacket type element included in a header of a link layer packet is‘110B’, a section table (or a descriptor) for signaling may be containedand transmitted in a payload of a link layer packet. The signalingsection table may include a signaling table/table section included inDVB-service information (SI), PSI/PSIP, non real time (NRT), ATSC 2.0,and mobile/handheld (MH), which are conventionally present.

FIG. 30 is a diagram illustrating a configuration of a link layer packetfor transmission of a framed packet, according to an embodiment of thepresent invention.

A packet used in a general network other than an IP packet or an MPEG-2TS packet may be transmitted through a link layer packet. In this case,a packet type element of a header of a link layer packet may have avalue of ‘111 B’, and the value may indicate that a framed packet isincluded in a payload of a link layer packet.

FIG. 31 is a diagram illustrating syntax of a framed packet, accordingto an embodiment of the present invention.

The syntax of the framed packet may include ethernet_type, length,and/or packet( ) fields. The ethernet_type field of 16 bits may identifya type of a packet in the packet( ) field according to an IANA registry.Here, only the registered values may be used. The length field of 16bits may set a total length of a packet( ) configuration in a byte unit.The packet( ) field with a variable length may include a network packet.

FIG. 32 is a diagram illustrating a receiver of a next-generationbroadcast system, according to an embodiment of the present invention.

The receiver according to an embodiment of the present invention mayinclude a receiving unit (not shown), a channel synchronizer 32010, achannel equalizer 32020, a channel decoder 32030, a signaling decoder32040, a baseband operation controller 32050, a service map database(DB) 32060, a transport packet interface 32070, a broadband packetinterface 32080, a common protocol stack processor 32090, a servicesignaling channel processing buffer & parser 32100, an audio/video (A/V)processor 32110, a service guide processor 32120, an applicationprocessor 32130, and/or a service guide DB 32140.

The receiver (not shown) may receive a broadcast signal.

The channel synchronizer 32010 may synchronize a symbol frequency andtiming so as to decode a signal received in a baseband. Here, thebaseband may refer to a region in which a broadcast signal istransmitted and received.

The channel equalizer 32020 may perform channel equalization on areceived signal. The channel equalizer 32020 may compensate for thereceived signal when the received signal is distorted due to amultipath, the Doppler Effect, and so on.

The channel decoder 32030 may restore the received signal to a transportframe having meaning. The channel decoder 32030 may perform forwarderror detection (FEC) on data or a transport frame contained in thereceived signal.

The signaling decoder 32040 may extract and decode signaling datacontained in the received signal. Here, the signaling data may includesignaling data and/or service information (SI), which will be describedlater.

The baseband operation controller 32050 may control signal processing ina baseband.

The service map DB 32060 may store signaling data and/or serviceinformation. The service map DB 32060 may store signaling data containedand transmitted in a broadcast signal and/or signaling data containedand transmitted in a broadband packet.

The transport packet interface 32070 may extract a transport packet froma transport frame or a broadcast signal. The transport packet interface32070 may extract signaling data or IP datagram from the transportpacket.

The broadband packet interface 32080 may receive a broadcast relatedpacket through the Internet. The broadband packet interface 32080 mayextract a packet acquired through the Internet and combine or extractsignaling data or A/V data from the corresponding packet.

The common protocol stack processor 32090 may process a received packetaccording to a protocol contained in a protocol stack. For example, thecommon protocol stack processor 32090 may perform processing in eachprotocol to process the received packet using the aforementioned method.

The service signaling channel processing buffer & parser 32100 mayextract signaling data contained in the received packet. The servicesignaling channel processing buffer & parser 32100 may extract signalinginformation associated with scan and/or acquisition of a service and/orcontent from IP datagram and so on and may parse the signalinginformation. Signaling data in the received packet may be present in apredetermined position or channel. The position or channel may bereferred to as a service signaling channel. For example, the servicesignaling channel may have a specific IP address, a UDP Port number, atransport session identifier, and so on. The receiver may recognize datatransmitted with the specific IP address, the UDP Port number, thetransport session, and so on as signaling data.

The A/V processor 32110 may perform decoding and presentation processingon received and video data.

The service guide processor 32120 may extract announcement informationfrom the received signal, manage the service guide DB 32140, and providea service guide.

The application processor 32130 may extract application data and/orapplication related information contained in the received packet andprocess the application data and/or application related information.

The service guide DB 32140 may store service guide data.

FIG. 33 is a diagram illustrating normal format of a section table,according to an embodiment of the present invention.

According to an embodiment of the present invention, the section tablemay include a table_id field, a section_syntax_indicator field, asection_length field, a version_number field, a current_next indicatorfield, a section_number field, a last_section_number field, and/or asection data field.

The table_id field may indicate a unique ID value of a correspondingtable.

The section_syntax_indicator field may indicate a format of a tablesection subsequent to a corresponding field. When a value of thecorresponding field is 0, the value may indicate that a correspondingtable section is a short format. When a value of the corresponding fieldis 1, the corresponding table section follows a normal long format.According to an embodiment of the present invention, a correspondingfield value may always have a fixed value 1.

The section_length field may indicate a length of a correspondingsection. A length to a last part of the corresponding section from anext field of the corresponding field may be indicated in a byte unit.

The version_number field may indicate a version of a correspondingtable.

When a value of the current_next_indicator field is 1, the value mayindicate that a corresponding section table is effective, and when thevalue is 0, the value may indicate that a section table for nexttransmission is effective.

The section_number field may indicate a number of a section included inthe corresponding table. In the case of a first section contained in thecorresponding table, a value of the section_number field may be 0 andmay be gradually increased.

The last_section_number field may refer to a number of a last sectionamong sections included in a corresponding table.

The section data field may include data including a correspondingsection.

In the drawing, a field denoted by Specific Use may refer to a fieldthat is differently configured according to each table. A bit numberallocated to the field denoted by Specific Use may be maintained.

FIG. 34 is a diagram illustrating a structure of a link layer packet fortransmission of signaling, according to an embodiment of the presentinvention.

According to an embodiment of the present invention, when signalinginformation is transmitted using a link layer packet, a value of apacket type element may indicate 110B.

The drawing illustrates a structure of a header of a link layer packetduring transmission of signaling. Referring to the drawing, whensignaling is transmitted, a signaling type field of 2 bits is presentbehind the packet type element. The signaling type field may indicate atype of signaling to be transmitted. According to a signaling typefield, information of the remaining 3-bit parts of a fixed headersubsequent thereto and information about an extended header may bedetermined.

According to an embodiment of the present invention, when a value of asignaling type field is 00B, a signaling type is a section table type.In the case of the section table, a field contained in the tablecontains information about segmentation of a section and informationabout a length of the section, and thus the link layer packet mayindicate only a packet type and a signaling type and transmitted withoutseparate processing. When the signaling type is a section table form,the remaining 3 bits obtained by excluding a packet type element and asignaling type field from a fixed header part may be reserved for futureuse without being used. When the signaling type is a section table form,an extended header is not basically used, but when a length of a linklayer packet needs to be indicated, an extended header of 1 or 2 bytesmay be added and used as a length field.

According to an embodiment of the present invention, when a value of asignaling type field is 01B, the value may indicate that a signalingtype is a descriptor form. In general, the descriptor may be used as apart of the section table, and the descriptor corresponds to simplesignaling, and thus the descriptor may be transmitted in a correspondingsignaling type in order to transmit only the descriptor. The descriptormay have a shorter length than the section table, and thus a pluralityof descriptors may be contained and transmitted in one link layerpacket. According to an embodiment of the present invention, 3 bitscorresponding to an indicator part of a fixed header may be used toindicate the number of descriptors contained in one link layer packet.When a signaling type is a descriptor type, the length of the link layerpacket may be indicated using information about the length of thecorresponding descriptor, contained in the descriptor, without using anextended header. When the length of the link layer packet needs to beseparately indicated, an extended header of 1 or 2 bytes may be addedand used as a length field.

According to an embodiment of the present invention, a signaling typefield value 10B may be reserved for another type of signaling for futureuse.

According to an embodiment of the present invention, when a value of asignaling type field is 11 B, the value may indicate that a signalingtype is GSE-LLC. The GSE-LLC signaling may have a structure to besegmented. Accordingly, when a signaling type is GSE-LLC, the remaining3-bit fields obtained by excluding a packet type element and a signalingtype field from a fixed header part may be used as a segment ID. When asignaling type is GSE-LLC, an extended header of 2 bytes may be added,and the aforementioned extended header of 2 bytes may include a segmentsequence number (segment sequence number) of 4 bits and a length fieldof 12 bits.

According to an embodiment of the present invention, GSE-LLC may standfor generic stream encapsulation logical link control and refer to oneof two attached layers of a data link layer of an OSI model.

FIG. 35 is a diagram illustrating meaning of a value of a signaling typefield and information about a fixed header and extended headersubsequent to the signaling type field, according to an embodiment ofthe present invention.

According to an embodiment of the present invention, when a value of thesignaling type field is 00B, a field subsequent to the signaling typefield may not be present.

According to an embodiment of the present invention, when a value of thesignaling type field is 01B, a concatenation count field may be presentafter the signaling type field. The concatenation count field may bepresent when only a descriptor instead of a section table istransmitted. The concatenation count field may indicate the number ofdescriptors contained in a payload of a link layer packet. Theconcatenation count field will be described in detail.

According to an embodiment of the present invention, when a value of thesignaling type field is 11B, a segment ID (Seg_ID) field, a segmentsequence number (Seg_SN) field, and/or a length field may be presentafter the signaling type field. In the case of LLC signaling data thatcan be transmitted using DVB_GSE, the LLC signaling data may beautonomously segmented. The segment ID (Seg_ID) field may refer to an IDfor identifying a segmented segment when LLC data is segmented. Whensegments of the transmitted LLC data are combined as one, a receivingside may recognize that segments of each LLC data item are components ofthe same LLC data using a segment ID (Seg_ID) field. The segment ID(Seg_ID) may have a size of 3 bits and identify 8 segmentations. Thesegment sequence number (Seg_SN) field may refer to a sequence of eachsegment when LLC data is segmented. Since a front part of the LLC datacontains an index of a corresponding data table, when a receiverreceives packets, segmented segments need to be sequentially aligned.Link layer packets having payloads segmented from one LLC data item havethe same Seg_ID but have different Seg_SNs. A segment sequence number(Seg_SN) field may have a size of 4 bits. One LLC data item may besegmented to a maximum of 16 segments. The length field may indicate alength of LLC data corresponding to a payload of a current link layerpacket in a byte unit. Accordingly, a total length of the link layerpacket may be a value obtained by adding 3 bytes as a header length to avalue indicated by the length field.

According to an embodiment of the present invention, DVB_GSE may standfor DVB-generic stream encapsulation and refer to a data link layerprotocol defined by DVB.

FIG. 36 is a diagram illustrating the number of descriptors included ina payload of a link layer packet according to a concatenation countvalue, according to an embodiment of the present invention.

According to an embodiment of the present invention, the concatenationcount value may indicate that descriptors, the number of which isobtained by adding 1 to a value of the concatenation count field, areincluded in a payload of one link layer packet. Accordingly, a bitnumber allocated to the concatenation count field is 3 bits, and thus amaximum of 8 descriptors may be signaled to constitute one link layerpacket.

FIG. 37 is a diagram illustrating a procedure for encapsulating asection table in a payload when signaling information input to a payloadof a link layer packet is a section table, according to an embodiment ofthe present invention.

According to an embodiment of the present invention, one section tableis a payload of a link layer packet without changes, and in this case, avalue indicated by a packet type element is 110B (signaling), and avalue indicated by a signaling type field may be 00B (section table). Inthe drawing, the remaining 3 bits obtained by excluding a packet typeelement and a signaling type field from a fixed header may be reservedas a reserved field for other future use.

According to an embodiment of the present invention, fields contained inthe section table may include a field indicating a length of acorresponding section. The aforementioned field indicating the length ofthe corresponding section is always positioned in the same position inthe section table, and thus a field present in a point spaced apart froma start point of a payload of a link layer packet by a predeterminedoffset may be checked to identify a length of the payload. In the caseof a section table, a section_length_field with a length of 12 bits ispresent at a position spaced apart from a point in which a payload isstarted by 12 bits. The section_length_field may indicate a length to alast part of the section immediately after the section_length_field.Accordingly, a length of a part that is not included in thesection_length_field and a length of a header of a link layer packet maybe added to a value indicated by the section_length_field so as toderive a total length of a link layer packet. Here, the part (3 bytes)that is not included in the section_length_field may include a length ofa table_id field and section_length_field. In addition, the length of aheader of a link layer packet may be 1 byte. That is, a total length ofthe link layer packet may be a value obtained by adding 4 bytes to avalue indicated by the section_length_field.

According to an embodiment of the present invention, upon receiving alink layer packet including a section table, a receiving apparatuses mayacquire and use information about the corresponding section tablethrough a value of a table_id field with a length of 8 bits, which isimmediately after a fixed header of a link layer packet.

FIG. 38 is a diagram illustrating syntax of a network information table(NIT) according to an embodiment of the present invention.

According to an embodiment of the present invention, when a sectiontable for signaling is included and transmitted in a payload of a linklayer packet, a network information table indicating current broadcastnetwork related information as a section table may be included in apayload of a link layer packet.

According to an embodiment of the present invention, the networkinformation table may include a table_id field, asection_syntax_indicator field, a section_length field, a network_idfield, a version_number field, a current_next_indicator field, asection_number field, a last_section_number field, anetwork_descriptors_length field, a descriptor( ), atransport_stream_loop_length field, a broadcast_id field, anoriginal_network_id field, a delivery_system_descriptor_length field,and/or a delivery_system_descriptor( ).

According to an embodiment of the present invention, a description of afield having the same name as a field described with reference to adiagram illustrating a normal format of the aforementioned section tableamong fields contained in the network information table will besubstituted with the above description.

The network_id field may indicate a unique identifier of a currentlyused broadcast network.

The network_descriptors_length field may indicate a length of adescriptor that states network related information in a network level.

The descriptor( ) may indicate a descriptor that states network relatedinformation in a network level.

The transport_stream_loop_length field may indicate a length of a streamrelated information transmitted in a broadcast network.

The broadcast_id field may indicate a unique identifier of abroadcasting station present in a used broadcast network.

The original_network_id field may indicate a unique identifier of anoriginally used broadcast network. When the originally used broadcastnetwork is different from a currently used broadcast network, NIT mayinclude information about the originally used broadcast network throughthe original_network_id field.

The delivery_system_descriptor_length field may indicate a length of adescriptor that states detailed information related to a delivery_systemin a current broadcast network.

The delivery_system_descriptor( ) may indicate a descriptor includingdetailed information related to a delivery_system in a current broadcastnetwork.

FIG. 39 is a diagram illustrating syntax of a delivery system descriptorincluded in a network information table (NIT), according to anembodiment of the present invention.

According to an embodiment of the present invention, the delivery systemdescriptor may include information about a physical layer pipe (PLP) fortransmitting signaling data and so on, related to data items transmittedby a specific broadcasting station in a delivery system.

According to an embodiment of the present invention, the delivery systemdescriptor may include a descriptor_tag field, a descriptor_lengthfield, a delivery_system_id field, a base_PLP_id field, abase_PLP_version field, and/or a delivery_system_parameters( ).

The descriptor_tag field may indicate an identifier indicating that acorresponding descriptor is a delivery system descriptor.

The descriptor_length field may indicate a length of a correspondingdescriptor.

The delivery_system_id field may indicate a unique delivery systemidentifier of a used broadcast network.

The base_PLP_id field may indicate an identifier of a representativephysical layer pipe (PLP) for decoding components for configuring abroadcast service transmitted from a specific broadcasting stationidentified by the broadcast_id. Here, the PLP may refer to a data pipeof a physical layer and a broadcast service transmitted from a specificbroadcasting station may include PSI/SI information and so on.

The base_PLP_version field may indicate version information according tochange in data transmitted through a PLP identified according to thebase_PLP_id. For example, when service signaling such as PSI/SI istransmitted through the base_PLP, a value of the base_PLP_version fieldmay be increased on a 1-by-1 basis whenever service signaling ischanged.

The delivery_system_parameters( ) may include a parameter indicatingbroadcast transmitting system characteristics. The parameter may includea bandwidth, a guard interval, a transmission mode, a center frequency,and so on.

FIG. 40 is a diagram illustrating syntax of a fast information table(FIT) according to an embodiment of the present invention.

According to an embodiment of the present invention, when a sectiontable for singling is included and transmitted in a payload of a linklayer packet, a fast information table (FIT) as a section table may beincluded in the payload of the link layer packet. According to anembodiment of the present invention, a receiving apparatus may rapidlyand easily scan and acquire a broadcast service through the FIT.

According to an embodiment of the present invention, the FIT may includea table_id field, a private_indicator field, a section_length field, atable_id_extension field, a FIT_data_version field, acurrent_next_indicator field, a section_number field, alast_section_number field, a num_broadcast field, a broadcast_id field,a delivery_system_id field, a base_PLP_id field, a base_PLP_versionfield, a num_service field, a service_id field, a service_categoryfield, a service_hidden_flag field, a SP_indicator field, anum_component field, a component_id field, and/or a PLP_id field.

According to an embodiment of the present invention, a description of afield having the same name as a field described with reference to adiagram illustrating a normal format of the aforementioned section tableamong fields contained in the FIT will be substituted with the abovedescription.

The table_id field may indicate that a corresponding table includesinformation related to rapid scan of a service and indicate that thecorresponding table corresponds to a fast information table.

The private_indicator field may always be set to 1.

The table_id_extension field may provide a scope of reserved fields thatlogically correspond to a portion of the table_id field.

The FIT_data_version field may indicate syntax included in a fastinformation table and version information about semantics. According toan embodiment of the present invention, a receiving apparatus maydetermine whether signaling contained in a corresponding table isprocessed using the FIT_data_version field.

The num_broadcast field may indicate the number of broadcasting stationsthat transmit a broadcast service or content through a frequency or atransmitted transport frame.

The broadcast_id field may indicate a unique identifier of abroadcasting station that transmits a broadcast service or contentthrough a frequency or a transmitted transport frame. In the case of abroadcasting station that transmits MPEG-2 TS-based data, thebroadcast_id may have the same value as the transport_stream_id ofMPEG-2 TS.

The delivery_system_id field may indicate an identifier of a broadcasttransmitting system that applies and processes the same transportparameter in a used broadcast network.

The base_PLP_id field may indicate an identifier of a PLP fortransmitting broadcast service signaling transmitted by a specificbroadcasting station identified by the broadcast_id. The base_PLP_idfield may indicate an identifier of a representative physical layer pipe(PLP) for decoding components included in a broadcast servicetransmitted by a specific broadcasting station identified by thebroadcast_id. Here, the PLP may refer to a data pipe of a physical layerand the broadcast service transmitted by a specific broadcasting stationmay include PSI/SI information and so on.

The base_PLP_version field may refer to version information according tochange in data transmitted through a PLP identified by the base_PLP_id.For example, when service signaling such as PSI/SI is transmittedthrough the base_PLP, a value of the base_PLP_version field may beincreased on a 1-by-1 basis whenever service signaling is changed.

The num_service field may refer to the number of broadcast servicestransmitted by a broadcasting station identified by the broadcast_id ina corresponding frequency or a transport frame.

The service_id field may refer to an identifier for identifying abroadcast service.

The service_category field may refer to a category of a broadcastservice. For example, when a value of the service_category field is0x01, the value may indicate a basic TV, when the value is 0x02, thevalue may indicate a basic radio, when the value is 0x03, the value mayindicate an RI service, when the value is 0x08, the value may indicate aservice guide, and when the value is 0x09, the value may indicateemergency alerting.

The service_hidden_flag field may indicate whether a correspondingbroadcast service is hidden. When the service is hidden, thecorresponding service is a text service or a service that isautonomously used, and thus a receiving apparatus according to anembodiment of the present invention may ignore the aforementioned hiddenbroadcast service or hide it in a service list.

The SP_indicator field may indicate whether service protection isapplied to one or more components in a corresponding broadcast service.

The num_component field may indicate the number of components includedin a corresponding broadcast service.

The component_id field may indicate an identifier for identifying acorresponding component in a broadcast service.

The PLP_id field may indicate an identifier for identifying a PLP fortransmitting a corresponding component in a broadcast service.

FIG. 41 is a diagram illustrating a procedure for encapsulating adescriptor in a payload when signaling information input to a payload ofa link layer packet is a descriptor, according to an embodiment of thepresent invention.

According to an embodiment of the present invention, one or moredescriptors may be included in the payload of the link layer packet, andin this case, a value indicated by the packet type element may be 110B(signaling), and a value indicated by the signaling type field may be01B (descriptor). In the drawing, the remaining 3 bits obtained byexcluding a packet type element and a signaling type field from a fixedheader may indicate a count field indicating the number of descriptorscontained in a payload of one link layer packet. The payload of one linklayer packet may include a maximum of 8 descriptors.

According to an embodiment of the present invention, all descriptors mayinclude a descriptor_tag field of 1 byte and a descriptor_length fieldof 1 byte in a start part of the descriptor. According to an embodimentof the present invention, a length of a concatenated packet may beobtained using the aforementioned descriptor_length field. Thedescriptor_length field is always positioned at the same position in adescriptor, and thus a filed at a position spaced apart from a startpoint of a payload of a link layer packet by a predetermined offset maybe checked so as to recognize a length of the payload. In the case of adescriptor, the descriptor_length field with a length of 8 bits may bepresent a position spaced apart from a start point of the payload by 8bits. The descriptor_length field may indicate a length to a last partof the descriptor immediately after the corresponding field.Accordingly, a length (1 byte) of a part that is not included in thedescriptor_length field and a length (1 byte) of the descriptor_lengthfield may be added to a value indicated by the descriptor_length fieldso as to derive a length of one descriptor. In addition, lengths ofrespective descriptors may be added by as much as the number ofdescriptors indicated by the count field so as to derive a total lengthof the link layer packet. For example, according to an embodiment of thepresent invention, a second descriptor included in a payload of a linklayer packet may be started at a position spaced apart from a initialpart of the payload by as much as a length of a first descriptor and adescriptor_length field of the second descriptor is present at aposition spaced apart from the position at which the descriptor isstarted by a predetermined offset, and in this regard, the field may bechecked so as to derive a total length of the second descriptor. Duringthis process, each of one or more descriptor length included in thepayload of the link layer packet may be derived, and the sum of lengthsof respective descriptors and a length of a header of a link layerpacket may be added so as to derive a total length of the link layerpacket.

According to an embodiment of the present invention, upon receiving alink layer packet including one or more descriptors, a receivingapparatus may acquire and use signaling information included in eachdescriptor through a value of the descriptor_tag field with a length of8 bits, included in each descriptor.

FIG. 42 is a diagram illustrating syntax of fast information descriptoraccording to an embodiment of the present invention.

According to an embodiment of the present invention, when a descriptorfor signaling is included and transmitted in a payload of a link layerpacket, the fast information descriptor may be included in the payloadof the link layer packet. According to an embodiment of the presentinvention, a receiving apparatus may rapidly and easily scan and acquirea broadcast service through the fast information descriptor.

According to an embodiment of the present invention, the fastinformation descriptor may include a descriptor_tag field, adescriptor_length field, a num_broadcast field, a broadcast_id field, adelivery_system_id field, a base_PLP_id field, a base_PLP_version field,a num_service field, a service_id field, a service_category field, aservice_hidden_flag field, and/or a SP_indicator field.

According to an embodiment of the present invention, a description of afield having the same name as a field included in the aforementioned FITamong fields contained in the FIT will be substituted with the abovedescription.

The descriptor_tag field may indicate that the corresponding descriptoris a fast information descriptor containing information related to rapidservice scan.

The descriptor_length field may indicate a length of a correspondingdescriptor.

FIG. 43 is a diagram illustrating a delivery system descriptor accordingto an embodiment of the present invention.

According to an embodiment of the present invention, when a descriptorfor signaling is included and transmitted in a payload of a link layerpacket, a delivery system descriptor may be included in the payload ofthe link layer packet. The delivery system descriptor m may includeinformation about a physical layer pipe (PLP) for transmitting signalingdata and so on associated with data items transmitted by a specificbroadcasting station in a delivery system.

According to an embodiment of the present invention, the delivery systemdescriptor may include a descriptor_tag field, a descriptor_lengthfield, a delivery_system_id field, a num_broadcast field, a base_PLP_idfield, a base_PLP_version field, a delivery_system_parameters_lengthfield, and/or a delivery_system_parameters( ).

The descriptor_tag field may indicate that a corresponding descriptor isa delivery system descriptor.

The descriptor_length field may indicate a length of a correspondingdescriptor.

The delivery_system_id field may indicate an identifier for identifyinga delivery system using the same parameter in a used broadcast network.

The num_broadcast field may indicate the number of broadcasting stationsthat transmit a broadcast service or content through a frequency or atransmitted transport frame.

The base_PLP_id field may indicate an identifier of a representativephysical layer pipe (PLP) for decoding components included in abroadcast service transmitted by a specific broadcasting stationidentified by the broadcast_id. Here, the PLP may refer to a data pipeof a physical layer, and the broadcast service transmitted from thespecific broadcasting station may include PSI/SI information and so on.

The base_PLP_version field may indicate version information according tochange in data transmitted through a PLP identified by the base_PLP_id.For example, when service signaling such as PSI/SI is transmittedthrough the base_PLP, a value of the base_PLP_version field may beincreased on a 1-by-1 basis whenever service signaling is changed.

The delivery_system_parameters_length field may indicate a length of adelivery_system_parameters( ) subsequent to a corresponding field.

The delivery_system_parameters( ) may include a parameter indicatingbroadcast transmitting system characteristics. The parameter may includea bandwidth, a guard interval, a transmission mode, a center frequency,and so on.

According to an embodiment of the present invention, the delivery systemdescriptor may be included and transmitted in the aforementioned networkinformation table (NIT). Syntax of the delivery system descriptor whenthe delivery system descriptor is included and transmitted in thenetwork information table has been described above with regard to thedescription of the network information table.

FIG. 44 is a diagram illustrating a procedure for encapsulating oneGSE-LLC item in a payload of one link layer packet when signalinginformation input to a payload of a link layer packet is a GSE-LLC typeused in the DVB-GSE standard, according to an embodiment of the presentinvention.

According to an embodiment of the present invention, the LLC data may bedivided into an index part and a record part, and the record part may bere-divided into several tables. Here, a table included in the recordpart may have a GSE table structure or a normal section table structure.

In the drawing, according to an embodiment of the present invention, oneLLC item may be a payload of one link layer packet, and in this case, avalue indicated by the packet type element may be 110B (signaling), anda value indicated by the signaling type field may be 11B (GSE-LLC).According to an embodiment of the present invention, when GSE-LLC typeof signaling is transmitted, the link layer packet may have an extendedheader of 2 bytes, and the aforementioned extended header of 2 bytes mayinclude a segment sequence number (Seg_SN) field of 4 bits and a lengthfield of 12 bits. The aforementioned length field may be allocated avalue indicating a total length of a link layer packet according to asystem configuration or allocate a value indicating a length of only apayload of a link layer packet.

FIG. 45 is a diagram illustrating a procedure for encapsulating oneGSE-LLC data item in payloads of a plurality of link layer packets whensignaling information input to a payload of a link layer packet is aGSE-LLC type used in the DVB-GSE standard, according to an embodiment ofthe present invention.

According to an embodiment of the present invention, when the LLC datais segmented, values of the Seg_ID field may be the same in order toindicate that data is segmented from the same LLC data.

According to an embodiment of the present invention, the Seg_SN fieldmay include sequence information of the segmented segments such that areceiving apparatus receives the segmented LLC data and recombines thesegmented data according to an order. When one LLC data item is includedin a payload of one link layer packet, a value of the Seg_SN field maybe 0.

According to an embodiment of the present invention, a receivingapparatus may recognize the number of segmented obtained by segmentingthe LLC data with respect to the corresponding Seg_ID through the LLCindex part.

FIG. 46 is a diagram illustrating a method for transmitting signalinginformation according to an embodiment of the present invention.

According to an embodiment of the present invention, the signalinginformation transmitting method may include generating a link layerpacket including signaling information (S14010) and/or transmitting thegenerated link layer packet (S14020). In the generating of the linklayer packet including the signaling information (S14010), the linklayer packet may include a fixed header and a payload, and the signalinginformation may include information about a broadcast program and dataand information required to receive a broadcast program and data. Inaddition, the signaling information may be included in a payload of alink layer packet. The aforementioned fixed header may include a packettype element for identifying a type of data included in a payload of alink layer packet according to an embodiment of the present inventionand a signaling type element for identifying a type of signalinginformation included in the payload of the link layer packet accordingto an embodiment of the present invention. A transmitting side maytransmit the link layer packet generated via the aforementionedprocedure (S14020). The link layer packet, the packet type element, andthe signaling type element have been described above in detail.

According to another embodiment of the present invention, a type ofsignaling information identified by the aforementioned signaling typeelement may be a section table.

According to another embodiment of the present invention, a type ofsignaling information identified by the aforementioned signaling typeelement may be a descriptor.

According to another embodiment of the present invention, a type ofsignaling information identified by the aforementioned signaling typeelement may be GSE-LLC. The signaling type element has been describedabove in detail.

According to another embodiment of the present invention, when one ormore descriptors are included in a payload of one link layer packet, theaforementioned fixed header may include a concatenation count fieldindicating the number of descriptors included in the payload of one linklayer packet. The count field has been described above in detail.

According to another embodiment of the present invention, when GSE-LLCdata is segmented to one or more segments and one segment of one or moresegments is included in a payload of one link layer packet, theaforementioned fixed header may include a segment identification elementfor identifying GSE-LLC to which a segment included in a payload of alink layer packet belongs. The segment identification element has beendescribed above in detail.

According to another embodiment of the present invention, theaforementioned link layer packet may include an extended header, and theaforementioned extended header may include a segment sequence elementindicating segment sequence information included in a payload of a linklayer packet, required for recombination of the aforementioned GSE-LLCdata, and/or a packet length element indicating a total length of thelink layer packet. The segment sequence element and the packet lengthelement have been described above in detail.

According to another embodiment of the present invention, theaforementioned total length of the link layer packet may indicate avalue obtained by adding a header length of the link layer packet and apayload length of the link layer packet, and when a payload includes asection table, the aforementioned length of the payload of the linklayer packet may indicate a length of a section table included in thepayload of the link layer packet. The aforementioned length of thesection table may indicate a value obtained by adding a value indicatedby the section_length_field at a position spaced apart from a start partof the section table by a predetermined offset, a length of thepredetermined offset, and a length of the section_length_field. Theaforementioned section_length_field may indicate a length to a last partof a corresponding section after the aforementionedsection_length_field. According to an embodiment of the presentinvention, the aforementioned predetermined offset may be 12 bits thatcorrespond to a value obtained by adding a table_id field length (8bits), a section_syntax_indicator field length (1 bit), a specific usefield length (1 bit), and a reserved field length (2 bit), which areincluded in the section table. The method for obtaining the length ofthe payload of the link layer packet has been described above in detail.

According to another embodiment of the present invention, theaforementioned payload of the link layer packet may include a fastinformation table or fast information descriptor including signalinginformation for rapid service scan and acquisition. The aforementionedfast information table and fast information descriptor have beendescribed above in detail.

FIG. 47 is a diagram illustrating a header of a link layer packet forRoHC transmission, according to an embodiment of the present invention.

In an IP-based broadcast environment, an IP packet may also beencapsulated and transmitted as the aforementioned link layer packet.When streaming is performed in the IP-based broadcast system, headerinformation of the IP packet may be barely changed and may bemaintained. Based on this point, the header of the IP packet may beencapsulated.

A robust header compression (RoHC) scheme may be mainly used toencapsulate a header (=IP header) of an IP packet. The present inventionproposes an encapsulation method when an RoHC packet is input to a linklayer.

When the RoHC packet is input to a link layer, a value of theaforementioned packet type element may be 010_(B). As described above,the value may indicate that a packet transmitted to a link layer from ahigher layer is a compressed IP packet.

When the RoHC packet is input, a header of the link layer packet mayinclude a fixed header and/or an extended header like the otheraforementioned packets.

The fixed header may include a packet type field and/or a packetconfiguration (PC) field. The fixed header may have a total size of 1byte. Here, the packet type field may have a value of 010 in the case ofthe compressed IP packet. The extended header may have a variable orfixed size in some embodiments.

The PC field of the fixed header may indicate a form in which an RoHCpacket included in a payload of a link layer packet is processed.According to a value of the PC field, the remaining part of a fixedheader subsequent to the PC field and information of the extended headermay be determined. In addition, the PC field may contain lengthinformation of an extended header according to a form in which the RoHCpacket is processed. The PC field may have a size of 1 bit.

A case in which a value of the PC field is 0_(B) will now be described.

When the PC field has a value 0_(B), the payload of the link layerpacket includes one RoHC packet or two or more RoHC packets areconcatenation. Concatenation may refer to the case in which packets witha short length are connected to configure a payload of a link layerpacket.

When a value of the PC field is 0_(B), a common CID indicator (CI) fieldof 1 bit and a count field of 3 bits may be subsequent to the PC field.Accordingly, the common CID information and a length part may be addedto the extended header. The length part may indicate a length of an RoHCpacket.

The common CID indicator (CI) field may be set to 1 when context IDs(CIDs) of RoHC packets included in a payload of one link layer packetare the same, and otherwise, the CI field may be set to 0. When the CIvalue is 1, an overhead processing method for a common CID may beapplied. The CI field may be 1 bit.

The count field may indicate the number of RoHC packets included in apayload of one link layer packet. That is, with regard to concatenation,the number of concatenated RoHC packets may be indicated by the countfield. The count field may be 3 bits. Accordingly, as shown in thefollowing table, a maximum of 8 RoHC packets may be included in apayload of one link layer packet. When the count field has a value of000, the value may indicate that RoHC packets are not concatenated andone RoHC packet is included in a payload of a link layer packet.

TABLE 1 Count (3 bits) No. of Concatenated RoHC packets 000 1 001 2 0103 011 4 100 5 101 6 110 7 111 8

As described above, the length part may indicate a length of the RoHCpacket. In the case of the RoHC packet, length information is deletedfrom a header of the RoHC packet. Accordingly, a length field in theheader of the RoHC packet cannot be used.

Accordingly, the header of the link layer packet may include a lengthpart such that a receiver recognizes a length of a corresponding RoHCpacket.

When a maximum transmission unit (MTU) is not determined, an IP packetmay have a maximum length of 65535 bytes. Accordingly, lengthinformation of 2 bytes is required in order to support an RoHC packet upto a maximum length. In addition, when a plurality of RoHC packets isconcatenated, a length field may be added by as much as the numberdetermined by the count field. In this case, the length part may includea plurality of length fields. However, when one RoHC packet is includedin a payload, the length part may include only one length field. Lengthfields may be arranged in the same way as an order of RoHC packetsincluded in a payload of a link layer packet. Each length field may havea value in a byte unit.

A common CID field may be a field in which a common CID is transmitted.A header part of the RoHC packet may include a context ID (CID) forchecking a relationship between compressed headers. The CID may bemaintained in the same value in a stable link state. Accordingly, RoHCpackets included in the payload of one link layer packet may include thesame CID. In this case, in order to reduce overhead, CID may be deletedfrom the header part of the RoHC packet included in concatenatedpayload, and a value of the common CID field may be indicated in aheader of the link layer packet. A receiver may recombine CIDs of theRoHC packet using the common CID field. When there is a common CIDfield, a value of the aforementioned CI field needs to be 1.

The case in which a value of the PC field 1_(B) will now be described.

When the value of the PC field is 1_(B), a payload of a link layerpacket includes segmented packets of an RoHC packet. Here, the segmentedpacket may refer to the case in which an RoHC packet with a long lengthis segmented to a plurality of segments and one of the segments isincluded in a payload of a link layer packet.

When a value of the PC field is 1_(B), a last segment indicator (LI) of1 byte and a segment ID field of 3 bits may be subsequent to the PCfield. In addition, in order to add information about segmentation, asegment sequence number field, a segment length ID field, a last segmentlength field, and so on may be added to an extended header.

A last segment indicator (L1) field may be used when an RoHC packet issegmented. The RoHC packet may be segmented to a plurality of segments.When an LI value is 1, the value may indicate that a segment included ina current link layer packet is a segment that is lastly positioned amongsegments segmented from one RoHC packet. When an LI value is 0, thevalue may indicate that a segment included in a current link layerpacket is not a last segment. The LI field may be used to determinewhether all segments are received when the receiver collects segments toreconfigure one RoHC packet. The LI field may be 1 bit.

A segment ID (Seg_ID) field may indicate an ID provided to an RoHCpacket when an RoHC packet is segmented. Segments from one RoHC packetmay have a segment ID of the same value. When transmitted segments arecombined as one segment, the receiver may determine whether componentsare from the same RoHC packet using a segment ID. The segment ID fieldmay be 3 bits. Accordingly, segmentation of 8 RoHC packets may besimultaneously supported.

A segment sequencer number (Seg_SN) field may be used to check asequence of each segment when an RoHC packet is segmented. That is, linklayer packets having segments from one RoHC packet as a payload may havethe same Seg_lD but have different Seg_SNs. The Seg_SN may be 4 bits.Accordingly, one RoHC packet may be segmented to a maximum of 16segments.

A segment length ID (Seg_Len_ID) field may be used to indicate eachsegment length. However, the segment length ID field may be used toindicate a length of a segment except for a last segment among aplurality of segments. The length of the last segment may be indicatedby a length field of a last segment, which will be described below. Whena payload of a link layer packet is not a last segment of an RoHCpacket, that is, when a value of LI is 0, a segment length ID field maybe present.

In order to reduce overhead of a header, a length of a segment may belimited to 16. An input size of a packet may be determined according toa code rate of FEC processed in a physical layer. A length of a segmentmay be determined according to the input size and determined as theSeg_Len_ID. When a physical layer is operated irrespective of a segmentlength, the length of the segment may be determined as follows.Segment Length=Seg_Len_ID×Len_Unit+min_Len[bytes]  [Equation 1]

Here, a length unit (Len_Unit) may be a basic unit indicating a lengthof a segment and min_Len may refer to a minimum of a segment length. TheLen_Unit and the min_Len may have the same value in a transmitter and areceiver and it is effective in terms of system management when theLen_Unit and the min_Len are not changed after being determined once. Inaddition, the Len_Unit and the min_Len may be determined inconsideration of processing capability of FEC of a physical layer duringan initialization procedure of a system.

The following table summarizes a length of a segment, which isrepresented according to a Seg_Len_ID, and a length allocated to theSeg_Len_lD may be an embodiment and may be changed according to adesigner's intention. According to the present embodiment, a value ofthe Len_Unit may be 256 and a value of the min_Len may be 512.

TABLE 2 Seg_Len_ID Segment Length (byte) 0000  512 (=min_Len) 0001  7680010 1024 0011 1280 0100 1536 0101 1792 0110 2048 0111 2304 1000 25601001 2816 1010 3072 1011 3328 1100 3584 1101 3840 1110 4096 1111 4352

A last segment length (L_Seg_Len) field may be used when a segmentincluded in a payload of a link layer packet is a last segment of theRoHC packet. That is, when a value of the LI field is 1, the lastsegment length (L_Seg_Len) field may be used. An RoHC packet may besegmented with the same size from a front part using the Seg_Len_ID.However, in this case, a last segment may not be segmented to a sizeindicated by the Seg_Len_ID. Accordingly, a length of a last segment maybe directly indicated by the L_Seg_Len field. The L_Seg_Len field mayindicate 1 to 4095 bytes, which is changed in some embodiments.

FIG. 48 is a diagram illustrating a method for transmitting an RoHCpacket through a link layer packet according to Embodiment #1 of thepresent invention.

The present embodiment may correspond to the case in which one RoHCpacket is included in a payload of a link layer packet when the RoHCpacket is within a processing range of a physical layer. In this case,the RoHC packet may not be concatenated or segmented.

In this case, one RoHC packet may be a payload of a link layer packetwithout changes. A value of the packet type may be 010_(B), a value ofthe PC field may be 0_(B), and a value of a CI field may be 0_(B). Inthe case of the aforementioned count field, since one RoHC packet isincluded in a payload without changes (one), the RoHC packet may have avalue of 000_(B) as described above. Then a length field of 2 bytesindicating a length of the RoHC packet may be subsequent to the RoHCpacket. In this case, sine only one packet is included in a payload, alength part may include only one length field.

According to the present embodiment, a total of 3 bytes of a link layerheader may be added. Accordingly, when a length of a RoHC packetindicated by the length field is L bytes, a total length of the linklayer packet may be (L+3) bytes.

FIG. 49 is a diagram of a method for transmitting an RoHC packet througha link layer packet according to Embodiment #2 of the present invention.

According to the present embodiment, since the RoHC packet does notreach a processing range of a physical layer, a plurality of RoHCpackets are concatenated and are included in a payload of a link layerpacket (concatenation).

In this case values of the PC field and the CI field may be the same asin a case in which one RoHC packet is included in a payload. A countfield is subsequent to the PC field and the CI field. The count fieldmay have a value of 001_(B) to 111_(B) according to the number of RoHCpacket included in a payload, as described above.

Then length fields with a length of 2 bytes may be positioned subsequentto the count field by as much as the number indicated by the countfield. The length field may be referred to as a length part.

Here, when a value indicated by the count field is n, RoHC packets R₁,R₂, . . . , R_(n) with a length of L₁, L₂, . . . , L_(n) may beconcatenated in a payload of a link layer packet.

A total extended header may have a length of 2n bytes. A total lengthL_(T) of a link layer packet may be represented according to thefollowing equation.

$\begin{matrix}{L_{T} = {1 + {2n} + {\sum\limits_{k = 1}^{n}{L_{k}\mspace{14mu}\lbrack{bytes}\rbrack}}}} & \left\lbrack {{Equation}\mspace{14mu} 2} \right\rbrack\end{matrix}$

FIG. 50 is a diagram illustrating a method for transmitting an RoHCpacket of a link layer packet according to Embodiment #3 of the presentinvention.

According to the present embodiment, when a plurality of RoHC packets isconcatenated to configure a payload of a link layer packet, theconcatenated RoHC packets have the same context ID (CID).

When the RoHC packets have the same CID, even if the CID is marked andtransmitted once, a receiver may restore an RoHC packet and a headerthereof to an original state. Accordingly, a CID common to RoHC packetsmay be extracted and transmitted once, and in this case, overhead may bereduced.

In this case, a value of the aforementioned CI field may be 1. Thismeans that processing is performed on the same CID. RoHC packets havingthe same CID may be represented by [R1, R2, R3, . . . , Rn]. The commonCID may be referred to as Common CID. A packet obtained by excluding aCID from a header of an RoHC packet may be denoted by R′k (k is 1, 2, .. . . n).

A payload of a link layer packet may include R′k (k is, 2, . . . , n). Acommon CID field may be added to a last part of an extended header of alink layer packet. The common CID field may be a field in which a commonCID is transmitted. The common CID field may be transmitted to one partof the extended header or transmitted to one part of the payload of thelink layer packet. According to system management, the common CID fieldmay be appropriately reordered at a position in which a position of thecommon CID field can be checked.

A size of the common CID field may be changed according to aconfiguration of the RoHC packet.

When the configuration of the RoHC packet is a small CID configuration,a size of a CID of the RoHC packet may be 4 bits. However, when a CID isextracted from the RoHC packet and is reordered, an add-CID octet may beentirely processed. That is, the common CID field may have a length of 1byte. Alternatively, an add-CID octet of 12 byte may be extracted fromthe RoHC packet, only a CID of 4 bits may be allocated to a common CIDfield, and the remaining 4 bits may be reserved for future use.

When a configuration of the RoHC packet is a large CID configuration, aCID size of the RoHC packet may have a length of 1 byte or 2 bytes. Thesize of the CID may be determined during an RoHC initializationprocedure. According to the size of the CID, the common CID field mayhave a length of 1 byte or 2 bytes.

According to the present embodiment, a length of a payload of a linklayer packet may be calculated as follows. Lengths of n RoHC packets R₁,R₂, . . . , R_(n) having the same CID may be referred to as L₁, L₂, . .. , L_(n), respectively. When a length of a header of a link layerpacket is L_(H), a length of a common CID field is L_(CID), and a totallength of a link layer packet is L_(T), L_(H) may be represented asfollows.L _(H)=1+2n+L _(CID)bytes  [Equation 3]

In addition, L_(T) may be calculated as follows.

$\begin{matrix}{L_{T} = {L_{H} + {\sum\limits_{k = 1}^{n}{\left( {L_{k}\; - L_{CID}} \right)\mspace{14mu}{bytes}}}}} & \left\lbrack {{Equation}\mspace{14mu} 4} \right\rbrack\end{matrix}$

As described above, L_(CID) may be determined according to a CIDconfiguration of RoHC. That is, in the case of a small CIDconfiguration, L_(CID) may be 1 byte, and in the case of a large CIDconfiguration, L_(CID) may be 1 byte or 2 bytes.

FIG. 51 is a diagram illustrating a method for transmitting a RoHCpacket through a link layer packet according to Embodiment #4 of thepresent invention.

According to the present embodiment, when an input RoHC packet exceeds aprocessing range of a physical layer (segmentation), segmented segmentsmay each be encapsulated as a payload of a link layer packet.

In order to indicate that a payload of a link layer packet includessegmented RoHC packets, a value of the PC field may be 1_(B). A value ofthe LI field may be 1_(B) only when a segment corresponding to a lastpart of the RoHC packet is a payload, and a value of the LI field may be0_(B) with respect to the all remaining segments. A value of the LIfield may indicate information about an extended header of a link layerpacket. That is, when a value of the LI field is 0_(B), an extendedheader with a length of 1 byte may be added, and when a value of the L1field is 1_(B), an extended header with a length of 2 bytes may beadded.

In order to indicate segments are segmented from the same RoHC packet,the Seg_ID needs to have the same value. In order to indicate a sequenceorder of segments for recombination of normal RoHC packets, a receivermay record a value of the Seg_SN, which is sequentially increased, in aheader.

During segmentation of the RoHC packet, a length of a segment may bedetermined to perform segmentation, as described above. A value of theSeg_Len_ID according to the length may be recorded in the header. Asdescribed above, the length of the last segment may be recorded directlyin an L_Seg_Len field of 12 bits.

Length information indicated using the Seg_Len_ID and the L_Seg_Lenfield may indicate only information about a segment, that is, a payloadof a link layer packet. Accordingly, total length information of a linklayer packet may be calculated by adding header lengths of the linklayer packet, which are known through the LI field.

During recombination of segments of a RoHC packet, a receiving sideneeds to check integrity of the recombined RoHC packet. To this end, CRCmay be added behind the IP packet during the segmentation procedure. Ingeneral, the CRC is added to a last part of the RoHC packet, and thusthe CRC may be included in the last segment after the segmentationprocedure.

FIG. 52 is a diagram illustrating a header of a link layer packet forRoHC transmission when MTU is 1500, according to an embodiment of thepresent invention.

In general, an RoHC scheme may be applied during video and audiostreaming. In this case, a maximum transmission unit (MTU) of the IPpacket may be set to 1500 bytes. This means that the RoHC packet alsohas a shorter length than 1500 bytes.

As described above, a PC field of the fixed header may indicate a formin which a RoHC packet included in a payload of a link layer packet isprocessed. According to a value of the PC field, information about theremaining part of the fixed header and the extended header, subsequentto the PC field, may be determined. In addition, the PC field mayinclude length information of an extended header according to the formin which the RoHC packet is processed. The PC field may have a size of 1bit.

The case in which a value of the PC field is 0_(B) will now bedescribed.

When the value of the PC field is 0_(B), a payload of a link layerpacket includes one RoHC packet or includes segmented packets of theRoHC packet. An SI field may be subsequent to the PC field. The segmentindicator (SI) may indicate whether the payload of the link layer packetincludes one RoHC packet or segments of the RoHC packet. According to avalue of the SI field, fields of the fixed header and extended headerparts may be determined.

As described above, the SI field may indicate whether the payload of thelink layer packet includes one RoHC packet or includes segments of theRoHC packet. In the case of a value of 0, the value may mean that thepayload includes one RoHC packet, and in the case of 1, the value mayman that the payload includes segments of the RoHC packet. The SI fieldmay be 1 byte.

A segment ID (Seg_ID) field may indicate an ID provided to an RoHCpacket when the RoHC packet is segmented. This is the same as theaforementioned Seg_ID field.

The segment sequencer number (Seg_SN) field may be used to check asequence of each segment when the RoHC packet is segmented. This is thesame as the aforementioned Seg_SN field.

The last segment indicator (LI) field may indicate whether a segmentincluded in a current link layer packet is a lastly positioned segmentamong segments segmented from the RoHC packet when the RoHC packet issegmented. This is the same as the aforementioned LI field.

A segment length ID (Seg_Len_ID) field may be used to indicate a lengthof each segment. This is the same as the aforementioned Seg_Len_lDfield. However, unlike in the aforementioned case, the number of lengthsof the segment may be limited to 8 instead of 16. In this case, a lengthof the segment represented according to a value of the Seg_Len_ID may besummarized according to the following table. A length allocated to theSeg_Len_lD is an embodiment and may be changed according to a designer'sintention. According the present embodiment, the Len_Unit may have avalue of 64 and the min_Len may have a value of 256.

TABLE 3 Seg_Len_ID Segment Length (byte) 000 256 (=min_Len) 001 320 010384 011 448 100 512 101 576 110 640 111 704

The last segment length (L_Seg_Len) field may be used to represent alength of a last segment. This is the same as the aforementionedL_Seg_Len field. However, unlike in the aforementioned case, theL_Seg_Len field may be represented in 1 to 2048 bytes. This may bemodified in some embodiments.

The case in which a value of the PC field is 1_(B) will now bedescribed.

When the value of the PC field is 1_(B),

two or more RoHC packets are concatenated in a payload of a link layerpacket. A common CID indicator (CI) field of 1 byte and a count field of3 bits may be subsequent to the PC field. Accordingly, common CIDinformation and a length part may be added to the extended header.

The common context ID indictor (CI) field may indicate whether contextIDs (CIDs) of RoHC packets included in a payload of one link layerpacket are the same. The CI field is the same as in the aforementionedcase.

The count field may indicate the number of RoHC packets included in apayload of one link layer packet. Unlike in the aforementioned countfield, a value 000 may be allocated to indicate that two RoHC packetsare concatenated. When a value of the count field is 111, the value mayindicate that 9 or more RoHC packets are concatenated. This may besummarized according to the following table.

TABLE 4 No. of Concatenated RoHC packets Count (3 bits) (MTU = 1500bytes) 000 2 001 3 010 4 011 5 100 6 101 7 110 8 111 9 or more packets,Extended length field is used

The length part may indicate a length of an RoHC packet. The length partmay include a plurality of length fields as described above. Each lengthfield may indicate a length of each RoHC packet.

According to the present embodiment, the MTU may be 1500 bytes, and thusthe length field may be allocated 11 bits as a minimum bit number inorder to indicate that the MTU is 1500 bytes. Since up to 2048 bytes canbe indicated by 11 bits, and thus when the MTU is extended to 2048 bytesfor future use, the method proposed by the present invention may beused. The length field may directly indicate a length thereof or mayindicate the length by mapping with a separate value. As describedabove, the length field may be added by as much as the number determinedby the counted field.

When the number of concatenated RoHC packets is 9 or more, the extendedlength part may be used to indicate a length of an RoHC packet after a9^(th) RoHC packet. That is, the extended length part may be used when avalue of the count field is 111_(B). The extended length part mayinclude a length field of 11 bits and an X field of 1 bit. The twofields may be alternately positioned.

The common CID field may be a field in which a common CID istransmitted. This may be the same as in the aforementioned common CIDfield.

FIG. 53 is a diagram illustrating a method for transmitting a RoHCpacket through a link layer packet when a MTU is 1500 according toEmbodiment #1 of the present invention.

According to the present embodiment, when the MTU is 1500, a PC fieldmay be 1 and a count value may not be 111_(B).

In this case, the length part may have length fields, the number ofwhich corresponds to the number determined by the count field value, asdescribed above. One length field is 11 bits, and thus a padding bit maybe added according to the number of length fields. That is, when anumber determined by the count field is k and a size of one length fieldis s (bit), a total length L_(LP) of a length part may be calculated asfollows.

$\begin{matrix}{L_{LP} = {\left\lceil \frac{k \times s}{8} \right\rceil\mspace{14mu}\lbrack{Bytes}\rbrack}} & \left\lbrack {{Equation}\mspace{14mu} 5} \right\rbrack\end{matrix}$

In addition, a size of the padding bit added to the length part may becalculated as follows.L _(padding)=(8×L _(LP))−(k×s)[Bits]  [Equation 6]

As described above, a length s of the length field may be 11 bits. Basedthereon, sizes of the length part and padding bit may be summarized asfollows.

TABLE 5 No. of Concatenated Count RoHC packets Size of Length Part Sizeof Padding (3 bits) (MTU = 1500 bytes) (Bytes) (bits) 000 2 3 2 001 3 57 010 4 6 4 011 5 7 1 100 6 9 6 101 7 10 3 110 8 11 1

FIG. 54 is a diagram illustrating a method for transmitting an RoHCpacket through a link layer packet when a MTU is 1500 according toEmbodiment #2 of the present invention.

According to the present embodiment, when the MTU is 1500, a PC field is1 and a count value is 111_(B). In this case, as described above, anextended length part may be added.

In this case, a length part in front of the extended length partincludes 8 length fields of 11 bits, and thus length part may have atotal length of 11 bytes. The count value is 111, and thus at least onelength field needs to exist in the extended length part.

As described above, the extended length part may include a length fieldof 11 bits and an X field of 1 bit. The two fields may be alternatelypositioned. The length part of the extended length part may be managedin the same way as the length field of the length part.

The X field may indicate whether a length field is further subsequent tothe X field. When a value of the X field is 0, the value may mean that alength field is not added any longer. When a value of the X field is 1,the value may mean that at least one length field and X field aresubsequent to the corresponding field. Accordingly, until a value of theX field is 0, the extended length part may be continuously increased. Itmay be seen that the number of RoHC packets positioned in a payload isadded by as much as the number of X fields.

In the extended length part, when the number of X fields with a value 1is m and a size of one length field is s (bit), a length L_(ELP) of theextended length part may be calculated as follows.

$\begin{matrix}{L_{ELP} = {\left\lceil \frac{\left( {m + 1} \right) \times \left( {s + 1} \right)}{8} \right\rceil\mspace{14mu}\lbrack{Bytes}\rbrack}} & \left\lbrack {{Equation}\mspace{14mu} 7} \right\rbrack\end{matrix}$

The extended length part may also have a padding bit in order to processa byte unit. A size of the padding bit added to the extended length partmay be calculated as follows.L _(E) _(_) _(paddng)=(8×L _(ELP))−((m+1)×(s+1))[Bits]  [Equation 8]

When the number of length fields is an odd number, a padding bit of 4bits may be added, and when the number of length fields is an evennumber, a padding bit may not be added.

FIG. 55 is a diagram illustrating a method for transmitting an RoHCpacket through a link layer packet when a MTU is 1500 according toEmbodiment #3 of the present invention.

According to the present embodiment, when the MTU is 1500, a RoHC packetis within a processing range of a physical layer, and thus one RoHCpacket is included in a payload of a link layer packet.

In this case, one RoHC packet may be a packet of a link layer packetwithout changes. A value of a packet type may be 010_(B), a value of thePC field may be 0_(B), and a value of the SI field may be 0_(B). Theaforementioned length part may be subsequent thereto. Here, the lengthpart may have one length field. The length field may be 11 bits. For 11bits, 3 bits of a fixed header and 1 byte of an extended header may beused for one length field.

In this case, a link layer header of total 2 bytes may be added.Accordingly, when a length of an RoHC packet, indicated by the lengthfield, is L bytes, a total length of the link layer packet is (L+2)bytes.

FIG. 56 is a diagram illustrating a method for transmitting an RoHCpacket through a link layer packet when a MTU is 1500 according toEmbodiment #4 of the present invention.

According to the present embodiment, the MTU is 1500, an input RoHCpacket exceeds a processing range of a physical layer (segmentation),and the segmented segments are encapsulated as a payload of a link layerpacket.

In order to indicate segmentation, a value of the SI field may be 1.

As described above, the Seg_ID needs to have the same value and theSeg_SN needs to have a value that is sequentially increased. The LIfield may have a value of 1 only in the case of a last segment and mayhave a value of 0 in the remaining cases. In addition, a length of eachsegment may be indicated using the Seg_Len_ID and the L_Seg_Len field. Adetailed method for indicating a length may be the same as in theaforementioned case.

Total length information of a link layer packet may be calculated byadding a header length of a link layer packet, which can be knownthrough the LI field. In addition, in order to check integrity during aprocedure for recombining segments of an RoHC packet, a receiving sidemay add CRC. The CRC may be added to a last segment.

FIG. 57 is a diagram illustrating a method for transmitting an RoHCpacket through a link layer packet when a MTU is 1500 according toEmbodiment #5 of the present invention.

According to the present embodiment, when the MTU is 1500, an RoHCpacket does not reach a processing range of a physical layer, and aplurality of RoHC packets are concatenated and included in a payload ofa link layer packet (concatenation).

According to the present embodiment, 8 or less RoHC packets may beconcatenated. In this case, an extended length part may not be required.A value of the PC field may be 1 and a value of the CI field may be 0.As described above, a value of the count field may be 000_(B) to110_(B).

Here, when a value indicated by the count field is n, RoHC packets R₁,R₂ . . . . . R_(n) with lengths L₁, L₂, . . . , L_(n) may beconcatenated in a payload of a link layer packet. Each length field mayhave a length of 11 bits. As necessary, a padding bit may be positionedsubsequent to the length field.

A total length L_(T) of a link layer packet may be represented asfollows

$\begin{matrix}{L_{T} = {1 + L_{LP} + {\sum\limits_{k = 1}^{n}{L_{k}\mspace{14mu}\lbrack{bytes}\rbrack}}}} & \left\lbrack {{Equation}\mspace{14mu} 9} \right\rbrack\end{matrix}$

Here, L_(LP) may be a total length of a length part and L_(k) may be alength of each RoHC packet.

FIG. 58 is a diagram illustrating a method for transmitting an RoHCpacket through a link layer packet when a MUT is 1500 according toEmbodiment #6 of the present invention.

According to the present embodiment, when the MTU is 1500, the RoHCpacket does not reach a processing range of a physical layer, and aplurality of RoHC packets are concatenated and included in a payload ofa link layer packet (concatenation).

However, according to the present embodiment, 9 or more RoHC packets maybe concatenated. In this case, an extended length part other than thelength part may be required. As described above, the count field mayhave a value of 111.

In an extended length part, when the number of X fields with a value of1 is m, the number n of RoHC packets concatenated in a payload of thelink layer packet may be 8+(m+1). In this case, a total length L_(T) ofthe link layer packet may be represented as follows.

$\begin{matrix}{L_{T} = {1 + L_{LP} + L_{ELP} + {\sum\limits_{k = 1}^{n}{L_{k}\mspace{14mu}\lbrack{bytes}\rbrack}}}} & \left\lbrack {{Equation}\mspace{14mu} 10} \right\rbrack\end{matrix}$

Here, L_(LP) may be a total length of the length part and L_(k) may be alength of each RoHC packet. Here, L_(ELP) may be a total length of theextended length part.

FIG. 59 is a diagram illustrating a method for transmitting an RoHCpacket through a link layer packet when a MTU is 1500 according toEmbodiment #7 of the present invention.

According to the present embodiment, the MTU is 1500, a plurality ofRoHC packets are concatenated and included in a payload of a link layerpacket. However, according to the present embodiment, concatenated RoHCpackets may have the same context ID (CID).

In this case, a value of the aforementioned CI field may be 1. This maymean that processing is performed on the same CID. RoHC packets havingthe same CID are represented by [R1, R2, R3, . . . , Rn]. A common CIDmay be referred to as a common CID. A packet except for a CID from aheader of a RoHC packet may be represented by R′k (k is 1, 2, . . . ,n).

A payload of a link layer packet may include R′k (k is 1, 2, . . . , n).A common CID field may be a field in which a common CID is transmitted.The common CID field may be transmitted in one part of the extendedheader or transmitted in one part of a payload of a link layer packet.According to system management, the common CID field may beappropriately at a position in which a position of the common CID fieldcan be checked.

A size of the common CID field may be varied according to aconfiguration of an RoHC packet.

When a configuration of an RoHC packet is a small CID configuration, asize of a CID of the RoHC packet may be 4 bits. However, when the CID isextracted and reordered in the RoHC packet, all add-CID octets may beprocessed. In addition, an add-CID octet of 1 byte is extracted from anRoHC packet, only a CID of 4 bits is allocated to a common CID field,and then the remaining 4 bits may be reserved for future use.

When a configuration of an RoHC packet is a large CID configuration, asize of a CID of an RoHC packet may be 1-byte or 2-bytes length. A sizeof the CID may be determined in an RoHC initialization procedure.According to the size of the CID, the common CID field may have a lengthof 1 byte or 2 bytes.

In this case, a total length L_(T) of a link layer packet may becalculated as follows.

$\begin{matrix}{L_{T} = {1 + L_{LP} + L_{CID} + {\sum\limits_{k = 1}^{n}{\left( {L_{k} - L_{CID}} \right)\mspace{14mu}\lbrack{bytes}\rbrack}}}} & \left\lbrack {{Equation}\mspace{14mu} 11} \right\rbrack\end{matrix}$

Here, L_(CID) may refer to a length of a common CID field. As describedabove, L_(CID) may be determined according to the CID configuration ofthe RoHC.

Using the same method, when n is 9 or more (when a value of the countfield is 111_(B)), a total length L_(T) of the link layer packet may becalculated as follows.

$\begin{matrix}{L_{T} = {1 + L_{LP} + L_{ELP} + L_{CID} + {\sum\limits_{k = 1}^{n}{\left( {L_{k} - L_{CID}} \right)\mspace{14mu}\lbrack{bytes}\rbrack}}}} & \left\lbrack {{Equation}\mspace{14mu} 12} \right\rbrack\end{matrix}$

Similarly, here, L_(CID) may refer to a length of a common CID field.

FIG. 60 is a diagram illustrating a configuration of a header of a linklayer packet when an IP packet is transmitted to a link layer, accordingto another embodiment of the present invention.

In this case, the header of the link layer packet may include a fixedheader and an extended header. The fixed header may have a length of 1byte and the extended header may have a fixed length or a variablelength. A length of each header may be changed according to a designer'sintention.

The fixed header may include a packet type field, a PC field, and/or acount field. According to another embodiment of the present invention,the fixed header may include a packet type field, a PC field, a LIfield, and/or a segment ID field.

The extended header may include a segment sequencer number field and/ora segment length ID field. According to another embodiment of thepresent invention, the extended header may include a segment sequencernumber field and/or a last segment length field.

Fields of the fixed header will be described below.

As described above, the packet type field may indicate a type of apacket input to a link layer. When the IP packet is input to the linklayer, a value of the packet type field may be 000B or 001B.

A packet configuration (PC) field may indicate the remaining part of asubsequent fixed header and/or a configuration of the extended header.That is, the PC field may indicate a type of an input IP packet.Accordingly, the PC field may contain information about a length of theextended header.

When a value of the PC field is 0, the value may mean that a payload ofa link layer packet includes one IP packet or two or more concatenatedIP packets. Here, concatenation may indicate that a plurality of packetswith a short length is connected to configure a payload.

In addition, when a value of the PC field is 0, a count field of 4 bitsmay be subsequent to the PC field. Here, the count field may indicatethe number of concatenated IP packets included in one payload. Thenumber of concatenated IP packets according to a value of the countfield will be described below.

In addition, when a value of the PC field is 0, a link layer may notinclude an extended header. However, in some embodiments, when a lengthof a link layer packet needs to be indicated, an extended header of 1-2bytes may be added. In this case, the extended header may be used toindicate the length of the link layer packet.

When a value of the PC field is 1, the value may mean that a payload ofa link layer packet includes segmented packets. Here, the segmentedpacket may indicate the number of segments segmented from an IP packetwith a long length. Each segmented segment may be referred to as asegment or a segmented packet. That is, when a value of the PC field is1, the payload of the link layer packet may include one segmentedpacket, that is, a segment.

When a value of the PC field is 1, an LI field of 1 bit and a segment IDfield of 3 bits may be subsequent to the PC field.

A last segment indicator (LI) field may indicate whether a correspondinglink layer packet includes a very last segment among segmented segments.That is, when a value of LI field is 1, a corresponding link layer mayinclude a very last segment among segmented segments, and when a valueof the LI field is 0, the corresponding link layer may not include thevery last segment. The LI field may be used to reconfigure an originalIP packet by a receiver. A value of the LI field may indicateinformation about an extended header of a link layer packet. That is,when a value of the LI field is 0, a length of the extended header maybe 1 byte, and when the value is 1, the length of the extended headermay be 2 bytes, which will be described below in detail.

The segment ID field may indicate an ID of a segment included in acorresponding link layer packet. When one IP packet is segmented,segments may be provided with the same ID. The segment ID may indicatethat segments are components of the same IP packet when the receiverreconfigures an original IP packet. The segment ID field has a size of 3bits, and thus segmentation of a total of 8 IP packets may besimultaneously supported.

In addition, when a value of the PC field is 1, an extended header maybe used for information about segmentation. As described above, theextended header may include a segment sequencer number, a segment lengthID field, and/or a last segment length field, etc.

Fields of the extended header will now be described.

When the aforementioned LI field has a value of 0, that is, when asegment included in a link layer packet is not a last segment, theextended header may include a segment sequencer number field and/or asegment length ID field.

The segment sequencer number field may include a sequencer of asegmented packet. Accordingly, link layer packets having segmentssegmented from one IP packet may have the same segment ID field but havedifferent segment sequencer number fields. The segment sequencer numberfield has a size of 4 bits, and thus one IP packet may be segmented to amaximum of 16 segments.

The segment length ID field may indicate lengths of segments that arenot a last segment. The lengths of the segments that are not a lastsegment may be the same. Accordingly, the lengths thereof may berepresented using a predetermined length ID. The segment length ID fieldmay indicate a length ID thereof.

A length of a segment may be set according to an input size of a packet,which is determined according to an FEC code rate of a physical layer.That is, the length of the segment may be determined according to theinput size thereof, and the segments thereof may be determined by asegment length ID. In order to reduce overhead of a header, a length ofa segment may be limited to 16.

A value of a segment length ID field according to a length of a segmentwill be described later.

When a physical layer operates irrespective of a length of a segment,the length of the segment may be obtained by adding a minimum segmentlength (min_Len) to multiplication of a segment length ID and a lengthunit (Len_Unit). Here, the Len_Unit may be a basic unit indicating alength of a segment and the min_Len may refer to a minimum of a segmentlength. The Len_Unit and the min_Len may always have the same value in atransmitter and a receiver, and it is effective in terms of systemmanagement when the Len_Unit and the min_Len are not changed after beingdetermined once. The Len_Unit and the min_Len may be determined inconsideration of processing capability of FEC of a physical layer duringan initialization procedure of a system.

When the aforementioned LI field has a value of 1, that is, when asegment included in a link layer packet is a last segment, an extendedheader may include a segment sequencer number field and/or a lastsegment length field.

The segment sequencer number field is the same as in the aforementionedcase.

The last segment length field may directly indicate a length of a lastsegment. When one IP packet is segmented to segments with a specificlength, the last segment may have a different length from othersegments. Accordingly, the last segment length field may directlyindicate a length of the last segment. The last segment length field mayindicate 1-4095 bytes. A byte number to be indicated may be different insome embodiments.

FIG. 61 is a diagram illustrating information indicated by each field ina header of a link layer packet when an IP packet is transmitted to alink layer, according to another embodiment of the present invention.

As described above, the number of concatenated IP packets may bedetermined according to a value of a count field (t61010). The value ofthe count field may refer to the number of concatenated IP packetswithout changes but may be meaningless when 0 packet is concatenated.Accordingly, the count field may indicate that IP packets, the number ofwhich is obtained by adding 1 to the value of the count field, areconcatenated. That is, as shown in Table (t61010), 0010 may indicatethat 3 IP packets are concatenated and 0111 may indicate that 8 IPpackets are concatenated.

Here, when a value of the count field is 0000, the value may indicatethat one IP packet is concatenated and indicate that a payload of a linklayer packet includes one IP packet without concatenate.

As described above, a length of a segmented segment may be representedby a value of a segment length ID field (t61020).

For example, when a value of the segment length ID field is 0000, asegment length may be 512 bytes. This may indicate that a segmentincluded in a payload of a corresponding link layer packet is not a lastsegment and has a length of 512 bytes. When other segments segmentedfrom the same IP packet of the segment are not a last segment, thesegment may have a length of 512 bytes.

In the tables, a length unit may have a value of 256 and a minimumsegment length may have a length of 512. Accordingly, the minimumsegment length may be 512 bytes (segment length ID field=0000). Inaddition, determined lengths of a segment may be increased with aninterval of 256 bytes.

FIG. 62 is a diagram illustrating the case in which one IP packet isincluded in a link layer payload with respect to a header of a linklayer packet when an IP packet is transmitted to a link layer, accordingto another embodiment of the present invention.

When one IP packet is included in a link layer payload, the case inwhich concatenation or segmentation is not performed may be referred toas encapsulation as a normal packet. In this case, an IP packet may bewithin a processing range of a physical layer.

According to the present embodiment, a link layer packet may have aheader of a total of 1 byte. A length of the header may be changed insome embodiments. A value of the packet type field may be 000 (in thecase of IPv4) or 001 (in the case of IPv6). The normal packetencapsulation procedure may be applied to IPv4 or IPv6 in the same way.A value of the PC field may be 0 since one packet is included in apayload. A subsequent count field may have a value of 0000 since onlyone packet is included in a payload.

According to the present embodiment, a payload of a link layer packetmay include one IP packet without changes.

According to the present embodiment, information of an IP packet headermay be used in order to check a length of a link layer packet. The IPpacket header may include a field indicating a length of an IP packet.The field may be referred to as a length field. A position of an IPpacket, in which the length field is positioned, may be fixed. Since oneIP packet is included in a payload of a link layer without changes, thelength field may be positioned at a position spaced apart from aninitial part of the payload of the link layer packet by a predeterminedoffset length. Accordingly, a total length of the payload of the linklayer may be known using the length field.

In the case of IPv4, the length field may be positioned at a positionspaced apart from a start point of a payload by 2 bytes, and in the caseof IPv6, the length field may be positioned at a position spaced apartfrom the start point of the payload by 4 bytes. The length field mayhave a length of 2 bytes.

In the case of IPv4, when a value of the length field is LIPv4 and aheader length of the link layer packet is LH (1 byte), a total length LTof a link layer packet may be represented according to the shownequation (t62010). Here, a value LIPv4 of the length field may indicatea total length of an IPv4 packet.

In the case of IPv6, when a value of the length field is LIPv6 and aheader length of the link layer packet is LH (I byte), a total length LTof a link layer packet may be represented according to the shownequation (t62020). Here, a value LIPv6 of the length field may indicateonly a length of a payload of an IPv6 packet, and thus a length (40bytes) of a fixed header of an IPv6 packet needs to be added in order toobtain the total length of the link layer packet.

FIG. 63 is a diagram illustrating the case in which a plurality of IPpackets are concatenated and included in a link layer payload withrespect to a header of a link layer packet when an IP packet istransmitted to a link layer, according to another embodiment of thepresent invention.

When an input IP packet does not reach a processing range of a physicallayer, a plurality of IP packets may be concatenated to be encapsulatedas a payload of one link layer packet.

According to the present embodiment, a link layer packet may have aheader with a total of 1 byte. A length of the header may be changed insome embodiments. A value of the packet type field may be 000 (in thecase of IPv4) or 001 (in the case of IPv6). An encapsulation procedureaccording to the present embodiment may be applied to IPv4 or IPv6 inthe same way. A value of the PC field may be 0 since a plurality ofconcatenated IP packets is included in a payload. A subsequent countfield may indicate the number of a plurality of concatenated IP packets(4 bits).

According to the present embodiment, a payload of a link layer packetmay include a plurality of IP packets. The IP packets may beconcatenated by connecting front and rear parts thereof and included ina payload of a link layer packet. A concatenation method may be changedaccording to a designer's intention.

According to the present embodiment, in order to check a length of alink layer packet, information of a header of a concatenated IP packetmay be used. Like the aforementioned normal packet encapsulation, alength field indicating a length of an IP packet may exist in a headerof the IP packet. In addition, the length fields may be positioned at afixed position in the IP packet.

Accordingly, when a header length of a link layer packet is LH and alength of each IP packet is Lk (here, k is equal to or more than 1 andis equal to or less than n), a total length LT of a link layer packetmay be represented according to the shown equation (t63010). That is,when a header length of a link layer packet is added to a value obtainedby summing lengths of IP packets indicated by length fields of IPpackets, a total length of the link layer packet may be obtained. Avalue of Lk may be checked by reading a length field of a header of eachIP packet.

FIG. 64 is a diagram illustrating the case in which one IP packet issegmented and included in a link layer payload with respect to a headerof a link layer packet when an IP packet is transmitted to a link layer,according to another embodiment of the present invention.

When an input IP packet exceeds a processing range of a physical layer,one IP packet may be segmented to a plurality of segments. The segmentedsegments may be encapsulated in a payload of each link layer packet.

According to the present embodiment, link layer packets t64010, t64020,and t64030 may each have a fixed header and an extended header. Lengthsof the fixed header and the extended header may be changed in someembodiments. A value of a packet type field may be 000 (in the case ofIPv4) or 001 (in the case of IPv6). An encapsulation procedure accordingto the present embodiment may be applied to IPv4 or IPv6 in the sameway. A value of the PC field may be 1 since segmented segments areincluded in a payload.

The link layer packets t64010 and t64020 having segments that are not alast segment as a payload may have a LI field value of 0 and the segmentID fields may have the same value. This is because the segments aresegmented from the same IP packet. A subsequent segment sequencer numberfield may indicate a sequence of a corresponding segment. Here, asegment sequence field value of the first link layer packet t64010 mayindicate that a corresponding link layer packet has a first segment as apayload. A segment sequence field value of the second link layer packett64020 may indicate that a corresponding link layer packet has a secondsegment as a payload. The segment length ID field may represent a lengthof a segmented segment with a predetermined length ID.

The link layer packet t64030 having a last segment as a payload may havea LI field value of 1. Here, the segment ID field may be the same asother link layer packets. This is because a last segment is alsosegmented from the same IP packet. A subsequent segment sequencer numberfield may indicate a sequence of a corresponding segment. A last segmentlength field may directly indicate a length of a last segment of thelink layer packet t64030.

According to the present embodiment, in order to check a length of alink layer packet, a segment length ID field or a last segment lengthfield may be used. The respective fields indicate only a length of apayload of a corresponding link layer packet, and thus a header lengthof a link layer packet needs to be added in order to obtain a totallength of the link layer packet. The header length of the link layerpacket may be known from the LI field, as described above.

FIG. 65 is a diagram illustrating link layer packets having segmentedsegments with respect to a header of a link layer packet when an IPpacket is transmitted to a link layer, according to another embodimentof the present invention.

According to the present embodiment, it is assumed that an IP packet of5500 bytes is input. Since a value obtained by dividing 5500 by 5 is1100, each segment may be configured with a length of 1024 bytes closestto the value. In this case, a last segment may be 1404 bytes(010101111100B). Segmented segments may be referred to as S1, S2, S3,S4, and S5, respectively, and headers corresponding thereto may bereferred to as H1, H2, H3, H4, and H5, respectively. The headers may beadded to the segments to generate respective link layer packets.

When an input IP packet is an IPv4 packet, packet type fields of H1 toH5 may have a value of 000. In addition, a PC field value of H1 to H5may have a segmented packet as a payload and thus may be 1.

An LI value of H1 to H4 does not have a last segment as a payload andthus may be 0. An LI value of H5 has a last segment as a payload andthus may be 1. Seg_ID, that is, a segment ID field of H to H5 hassegments from the same packet as a payload and thus may have the samevalue (000).

Seg_SN, that is, a segment sequencer number field of H1 to H5 maysequentially represent H1 to H5 as 0000B to 0100B. A segment length IDfield of H1 to H4 may have a value of 0010 corresponding to an ID of a1024-byte length. A segment length field of H5 may have a value of010101111100 indicating 1404 bytes.

FIG. 66 is a diagram illustrating a method for using CRC encoding withrespect to a header of a link layer packet when an IP packet istransmitted to a link layer, according to another embodiment of thepresent invention.

When an IP packet is segmented and processed as a link layer packet, areceiver needs to receive a plurality of link layer packets to recombinean original IP packet. The receiver may need to check integrity of therecombined IP packet.

To this end, CRC encoding may be used. Prior to segmentation of an IPpacket, CRC may be added subsequent to the IP packet. When an IP packetto which CRC is added is segmented, a link layer packet including a lastsegment may also include CRC. The receiver may check the CRC anddetermine whether recombination is successful without errors.

In general, the CRC may be added to a last part of a packet but may bepositioned at another position in some embodiments.

FIG. 67 is a diagram illustrating a configuration of a link layer packetwhen signaling information is transmitted to a link layer according toanother embodiment of the present invention.

In this case, a header of a link layer packet may include a fixed headerand an extended header. The fixed header may have a length of 1 byte andthe extended header may have a fixed length or a variable length. Alength of each header may be changed according to a designer'sintention.

The fixed header may include a packet type field, a PC field, and/or aconcatenation count field. According to another embodiment of thepresent invention, the fixed header may include a packet type field, aPC field, an LI field, and/or a segment ID field.

The extended header may include a signaling class field, an informationtype field, and/or a signaling format field. According to anotherembodiment of the present invention, the extended header may furtherinclude a payload length part. According to another embodiment of thepresent invention, the extended header may include a segment sequencernumber field, a segment length ID field, a signaling class field, aninformation type field, and/or a signaling format field. According toanother embodiment of the present invention, the extended header mayinclude a segment sequencer number field and/or a segment length IDfield. According to another embodiment of the present invention, theextended header may include a segment sequencer number field and/or alast segment length field.

The fields of the fixed header will now be described.

As described above, the packet type field may indicate a type of apacket input to a link layer. When signaling information is input to alink layer, a value of the packet type field may be 110B.

The PC field, the LI field, the segment ID field, the segment sequencernumber field, the segment length ID field, and the last segment lengthfield are the same as the aforementioned fields. The concatenation countfield may be the same as the aforementioned count field.

The fields of the extended header will now be described.

When the PC field has a value of 0, the extended header may include asignaling class field, an information type field, and/or a signalingformat field. In addition, according to a value of the signaling formatfield, the extended header may further include a payload length part.

The signaling class field may indicate a type of signaling informationincluded in a link layer packet. The signaling information indicated bythe signaling class field may be, for example, fast information channel(FIC) information or header compression information. The signalinginformation indicated by the signaling class field will be describedlater.

The information type field may indicate detailed information thereofwith respect to signaling information of a type indicated by thesignaling class field. The information type field may be separatelydefined according to a value of the signaling class field.

The signaling format field may indicate a format of signalinginformation included in a link layer packet. The format indicated by thesignaling format field may be a section table, a descriptor, XML, or thelike. The format indicated by the signaling format field will bedescribed later.

The payload length part may indicate a length of signaling informationincluded in a payload of a link layer packet. The payload length partmay be a combination of length fields indicating lengths of concatenatedsingling information items. Each length field may have a size of 2 bytesbut the size may be changed according to a system configuration. A totallength of the payload length part may be represented by the sum oflengths of the length fields. In some embodiments, a padding bit foralignment of bytes may be added. In this case, the total length of thepayload length part may be increased by as much as the padding bit.

Whether the payload length part exists may be determined according to avalue of the signaling format field. Like the section table and thedescriptor, when corresponding signaling information has a value of alength of the corresponding signaling information, a separate lengthfield may not be required. However, signaling information that does nothave a separate length value may require a separate length field. In thecase of signaling information that does not have a separate lengthvalue, a payload length part may exist. In this case, the payload lengthpart may include length fields, the number of which corresponds to thenumber of count fields.

When the PC field has a value of 1 and the LI field has a value of 1,the extended header may include a segment sequencer number field and/ora last segment length field. When the PC field has a value of 1 and theLI field has a value of 0, the extended header may include a segmentsequencer number field and/or a segment length ID field.

The segment sequencer number field, the last segment length field, andthe segment length ID field are the same as the aforementioned fields.

When the PC field has a value of 1 and the LI field has a value of 0, ifa payload of a corresponding link layer packet is a first segment, theextended header may further include additional information. Theadditional information may include a signaling class field, aninformation type field, and/or a signaling format field. The signalingclass field, the information type field, and the signaling format fieldare the same as the aforementioned fields.

FIG. 68 is a diagram illustrating information indicated by fields withrespect to a configuration of a link layer packet when signalinginformation is transmitted to a link layer, according to anotherembodiment of the present invention.

As described above, a type of signaling information included in a linklayer packet may be represented by a signaling class field (t68010).

For example, when a value of the signaling class field is 000, signalinginformation may be signaling information for a fast information channel(FIC). When a value of the signaling class field is 001, the signalinginformation may be signaling information for emergency alert. When avalue of the signaling class field is 010, the signaling information maybe signaling information for header compression. When a value of thesignaling class field is 011 to 110, the signaling class field may bereserved for a singling information type for future use. When a value ofthe signaling class field is 111, various types of signaling informationmay be included in the link layer packet.

A signaling information value indicated by the signaling class field maybe differently determined in some embodiments.

As described above, a format of signaling information included in thelink layer packet may be indicated by the signaling format field(t68020).

For example, when a value of the signaling format field is 00, thesignaling information may be included in a payload in the form of asection table. When a value of the signaling format field is 01, thesignaling information may be included in a payload in the form of adescriptor. When a value of the signaling format field is 10, thesignaling information may be included in a payload in the form of XML.When the signaling format field has a value of 11, the signalinginformation may be included in a payload in other forms.

A format indicated by the signaling format field may be differentlydetermined in some embodiments.

FIG. 69 is a diagram illustrating a configuration of a link layer packetwhen signaling information is one section table with respect to theconfiguration of the link layer packet when signaling information istransmitted to a link layer, according to another embodiment of thepresent invention.

According to the present embodiment, it is assumed that one sectiontable is encapsulated as one link layer packet.

According to the present embodiment, a header of a link layer packet mayinclude a packet type field with a value of 110. Since one signalinginformation item is included in a payload of a link layer packet, the PCfield may have a value of 0 and a concatenation count field may have avalue of 0000. The signaling class field and the information type fieldmay have a value according to data contained in the correspondingsection table. Since signaling information is a section table, thesignaling format field may have a value of 00.

According to the present embodiment, an input section table may bepositioned in a payload of a link layer packet without changes.

According to the present embodiment, in order to use a length of a linklayer packet, information of a section table may be used. As describedabove, a section table may include a field indicating a length of thecorresponding section table. The field may be referred to as a lengthfield. The length field may be positioned at a fixed position in thesection table. Since one section table is input to a payload of a linklayer without changes, a length field thereof may be positioned at aposition spaced apart from a start point of the payload of the linklayer packet by a predetermined offset. Accordingly, a total payloadlength of a link layer may be known using the length field. In the caseof a section table, a length field of 12 bits may be positioned at aposition spaced apart from the start point of the payload by 12 bits.The length field may be referred to as a Section_length field.

An Lsection of a length field may indicate a length to a last part of asection table immediately after the length field. Accordingly, when 3bytes of the remaining part of the section table and 2 bytes of a headerlength of a link layer packet may be added to obtain a total length ofthe link layer packet. That is, a total length Lt of the link layerpacket may be (Lsection+5) bytes.

Upon receiving a link layer packet according to the present embodiment,a receiver may process corresponding signaling information (sectiontable) using the signaling class field and/or the information typefield, etc. In addition, the receiver may check a value of a table ID (8bits) of the section table and process the corresponding signalinginformation.

FIG. 70 is a diagram illustrating a configuration of a link layer packetwhen signaling information is one descriptor with respect to theconfiguration of the link layer packet when signaling information istransmitted to a link layer, according to another embodiment of thepresent invention.

According to the present embodiment, it is assumed that one descriptoris encapsulated as one link layer packet.

According to the present embodiment, header information of the linklayer packet may correspond to encapsulation of one section table.However, the signaling class field and the information type field mayhave a value according to data contained in the correspondingdescriptor. In addition, since signaling information is a descriptor,the signaling format field may have a value of 01.

According to the present embodiment, an input descriptor may bepositioned in a payload of a link layer packet without changes.

According to the present embodiment, in order to check a length of alink layer packet, information of a descriptor may be used. This may besimilar to encapsulation of the aforementioned one section table.However, a position of a field indicating a length of a correspondingdescriptor may be changed in the descriptor. In the case of adescriptor, a length field may be positioned at a position spaced apartfrom a start point of a payload by 8 bits and may have a length of 8bits. Based thereon, a total length of the link layer packet may beknown.

Upon receiving a link layer packet according to the present embodiment,a receiver may process signaling information (descriptor) using thesignaling class field and/or the information type field, etc. Inaddition, the receiver may check a descriptor tag (8 bits) of adescriptor and process corresponding signaling information.

FIG. 71 is a diagram illustrating a configuration of a link layer packetwhen signaling information is a plurality of descriptors with respect tothe configuration of the link layer packet when signaling information istransmitted to a link layer, according to another embodiment of thepresent invention.

According to the present embodiment, a plurality of descriptors may beconcatenated and encapsulated in a payload of a link layer packet.

A header of a link layer packet according to the present embodiment mayinclude a packet type field of a value of 110 and a PC field of a valueof 0. The concatenation count field may indicate the number ofconcatenated descriptors. The signaling class field and the informationtype field may have a value according to data of a correspondingdescriptor. Since signaling information is a descriptor, the signalingformat field may have a value of 01.

A total length of a link layer packet according to the presentembodiment may be calculated using a similar method to concatenation ofIP packets. A value of a descriptor_length field of a descriptor may besequentially read by as much as the number indicated by the count fieldfrom a start point of a payload. The read values may be summed to obtaina total length of a payload of a link layer packet. Here, a headerlength of a link layer packet may be added to the resulting value toobtain a total length of a link layer packet.

FIG. 72 is a diagram illustrating a configuration of a link layer packetwhen signaling information is a plurality of section tables with respectto the configuration of the link layer packet when signaling informationis transmitted to a link layer, according to another embodiment of thepresent invention.

According to the present embodiment, a plurality of section tables maybe concatenated and encapsulated in a payload of a link layer packet.

A header of a link layer packet according to the present embodiment mayinclude a packet type field with a value of 110, a PC field with a valueof 0, and a concatenation count field indicating the number ofconcatenated section tables. The signaling class field and theinformation type field may have a value according to data ofcorresponding section tables. Since signaling information is a sectiontable, the signaling format field may have a value of 00.

A total length of a link layer packet according to the presentembodiment may be obtained similarly to the case in which theaforementioned descriptors are concatenated. As described above, alength field of 12 bits may be positioned at a position spaced apartfrom a start point of the section table by 12 bits in a section table. Alength of the remaining section table may be added to the length fieldto obtain a total length of a section table. Total lengths of sectiontables may be summed to obtain a total length of concatenated sectiontables, that is, a length of a link layer packet. Here, a header lengthof a link layer packet may be added to the resulting value to obtain atotal length of the link layer packet.

FIG. 73 is a diagram illustrating a configuration of a link layer packetwhen signaling information does not have a separate length value withrespect to the configuration of the link layer packet when signalinginformation is transmitted to a link layer, according to anotherembodiment of the present invention.

According to the present embodiment, the aforementioned signaling formatfield may indicate that corresponding signaling information is signalinginformation that does not have XML or a separate length value. Asdescribed above, an extended header may further include a payload lengthpart.

According to the present embodiment, a header may include a packet fieldwith a value of 110, a PC field with a value of 0, and a concatenationcount field indicating the number of concatenated signaling informationitems. The subsequent signaling class field and information type fieldmay have values according to data of the corresponding signalinginformation. Since the signaling information is XML or separatesignaling information, the signaling format field may have a value of 10or 11.

As described above, an added payload length part may include a pluralityof length fields. Each length field may indicate a length of eachsignaling information item. Accordingly, length fields, the number ofwhich corresponds to the number indicated by the concatenation countfield, may exist. The length field may have a length of 2 bytes. Alength of the length field may be changed according to a systemconfiguration. A padding bit for byte alignment may be further added toa link layer packet.

According to the present embodiment, in order to obtain a total lengthof a link layer packet, length fields may be used (t73010). When a valueindicated by the concatenation count field is n, a payload length partof a total of 2*n bytes may be added to a header. In addition, whenvalues of length fields indicating lengths of concatenated signalinginformation items S1, S2, . . . , Sn are L1, L2, . . . , Ln, if a headerlength of a link layer packet is 2 bytes, a total length LT of a linklayer packet may be represented as illustrated (t73010).

FIG. 74 is a diagram illustrating a configuration of a link layer packetwhen one signaling information item is segmented to a plurality ofsegments with respect to the configuration of the link layer packet whensignaling information is transmitted to a link layer, according toanother embodiment of the present invention.

When input signaling information exceeds a processing range of aphysical layer, one signaling information item may be segmented to aplurality of segments. Each segmented segment may be encapsulated in apayload of each link layer packet.

The configuration according to the present embodiment may have a similarheader configuration to the case in which the aforementioned IP packetis segmented. The packet type field may have a value of 110 whensignaling information is input. The PC field, the LI field, the segmentID field, the segment sequencer number field, the segment length IDfield, and the last segment length field may be the same as in theaforementioned case in which an IP packet is segmented.

According to the present embodiment, unlike in the aforementioned casein which the IP packet is segmented, a first packet may further includeadditional information (t74010). As described above, the additionalinformation may include a signaling class field, an information typefield, and/or a signaling format field. When a receiver receives allsegments, the additional information items may facilitate processing ofthe corresponding signaling information.

Information about an extended header of a link layer packet may be knownaccording to a combination of an LI field value of a segment sequencernumber field. When a value of the LI field is 0 and a value of a segmentsequencer number field is 0000 (i.e., in the case of a first segment), alength of the extended header may be 2 bytes. When a value of the LIfield is 0 and a value of the segment sequencer number field is not0000, a length of the extended header may be 1 byte. When a value of theLI field is 1, a length of the extended header may be 2 bytes.

A total length of a link layer packet may be obtained by adding a lengthof a header of a link layer packet to the length of the segment,calculated through the segment length ID field or the last segmentlength field.

Like in the case in which an IP packet is segmented, CRC encoding mayalso be used when signaling information is segmented. The CRC may beadded to a last part of the signaling information. The CRC may be usedto check integrity of recombination when a receiver recombines signalinginformation. When signaling information to which the CRC is added issegmented, a link layer packet including a last segment may also includeCRC.

In general, CRC may be added to a last part of a packet or may bepositioned at other positions in some embodiments.

FIG. 75 is a diagram illustrating a method for transmitting a broadcastsignal according to an embodiment of the present invention.

According to an embodiment of the present invention, the method fortransmitting the broadcast signal may include generating a plurality ofsignaling information items for signaling broadcast data (t75010),generating a link layer packet using the signaling information items(t75020), generating a broadcast signal using the link layer packet(t75030), and/or transmitting the broadcast signal (t75040).

First, a plurality of signaling information items may be generated(t75010). Here, the signaling information items may be used to signalother broadcast data transmitted through a link layer. The content andtype of signaling information may be changed in some embodiments. Thegenerating of the signaling information items may be performed by afirst module to be described later.

A link layer packet may be generated using the generated signalinginformation items (t75020). This step may correspond to a procedure forgenerating a link layer packet by concatenating the aforementionedsignaling information items. As described above, the link layer packetmay include a link layer header and a link layer payload. The link layerheader may include a packet type field, a packet configuration field,and a count field, and the packet type field may indicate thatinformation included in a link layer payload is signaling information.The packet configuration field may indicate whether a link layer payloadincludes a plurality of signaling information items and the count fieldmay indicate the number of the signaling information items included inthe link layer payload. Since the signaling information items areconcatenated, a plurality of signaling information items may beconcatenated and included in a link layer payload.

Here, the link layer header may refer to the aforementioned fixed headeror extended header or an entire header including the fixed header andthe extended header according to the context. The packet configurationfield may refer to the aforementioned PC field. The link layer payloadmay refer to a payload of a link layer packet. The generating of thelink layer packet may be performed by a second module to be describedlater.

A broadcast signal may be generated using the generated link layerpacket (t75030). In a physical layer, predetermined encoding,modulation, etc. may be applied to the link layer packet generated in alink layer. Through the link layer packet, the physical layer mayperform physical layer processing irrespective of a type of inputpacket/input signaling information. A broadcast signal may be generatedthrough the predetermined physical layer processing. The generating ofthe broadcast signal may be performed by a third module to be describedlater.

The broadcast signal may be transmitted to a receiver through thereceiver (t75040). The broadcast signal may be transmitted through abroadcast network and a transmitting method may be changed in someembodiments. The method for transmitting the broadcast signal may beperformed by a third module to be described later.

According to another embodiment of the present invention, in the methodfor transmitting the broadcast signal, a link layer header may furtherinclude a signaling class field, an information type field, and asignaling format field. The signaling class field may indicate asignaling target of signaling information, the information type fieldmay include data about the signaling information, and the signalingformat field may indicate a format of signaling information. Thesignaling class field, the information type field, and the signalingformat field may be the same as the aforementioned fields.

According to another embodiment of the present invention, in the methodfor transmitting the broadcast signal, a signaling format field mayindicate that a plurality of signaling information items including alink layer payload is a plurality of section tables. This may mean thata format of signaling information indicated by signaling format field isa section table.

According to another embodiment of the present invention, in the methodfor transmitting the broadcast signal, a length of a link layer headermay be determined according to a value of a signaling format field. Thatis, as described above, this is because whether a link layer headerfurther includes an additional payload length part is determinedaccording to a value of the signaling format field. In addition, alength of a link layer payload may be determined according to values ofsection_length_fields of a plurality of section tables. As describedabove, section_length_fields may exist in a fixed position in a sectiontable. A length of the link layer payload may be calculated based on thesum of values of the section_length_fields.

According to another embodiment of the present invention, in the methodfor transmitting the broadcast signal, section_length_fields of aplurality of section tables may be sequentially positioned on a linklayer payload. As described above, when section tables are concatenated,section_length_fields may be arranged with an interval in a link layerpayload. The length fields may be positioned at a position fixed from astart point of each section table. Lengths of the respective sectiontables may be different, and thus distance between the length fields maybe different. As described above, the section_length_field may indicatea length of a corresponding section table.

According to another embodiment of the present invention, in the methodfor transmitting the broadcast signal, a signaling format field mayindicate that a plurality of signaling information items including alink layer payload are a plurality of descriptors. This may be a case inwhich a plurality of descriptors may be concatenated to configure apayload, and as described above, may be indicated by the signalingformat field.

According to another embodiment of the present invention, in the methodfor transmitting the broadcast signal, a link layer header may furtherinclude a payload length part including a plurality of payload lengthfields. The payload length fields may refer to length fields of theaforementioned payload length part. As described above, the respectivepayload length fields may indicate a plurality of signaling informationitems. This may correspond to the case in which signaling informationincluded in the link layer packet has no separate length field.

According to another embodiment of the present invention, in the methodfor transmitting the broadcast signal, whether a link layer headerfurther includes a payload length part may be determined according to avalue of the signaling format field. When the signaling informationincluded in the link layer packet has no separate length field, a valueof the signaling format field may correspond to 1×. Accordingly, whethera payload length part exists may be recognized through a value of thesignaling format field.

According to another embodiment of the present invention, the method fortransmitting the broadcast signal may be a method in which theaforementioned segmentation is performed. In this case, the method fortransmitting the broadcast signal may include generating signalinginformation for signaling broadcast data, generating a link layer packetusing the signaling information, generating a broadcast signal using thelink layer packet, and/or transmitting the broadcast signal. Therespective steps may be performed by a first module, a second module,and a third module in the stated order.

In the method for transmitting the broadcast signal, a link layer packetmay include a link layer header and a link layer payload, and the linklayer payload may include one of segmented segments. The link layerheader may include a packet type field and a packet configuration field,and the packet type field may indicate that information including a linklayer payload is signaling information. The packet configuration fieldmay indicate whether a link layer payload includes one of segmentssegmented from signaling information.

According to another embodiment of the present invention, in the methodfor transmitting the broadcast signal, when a segment included in a linklayer payload is a first segment among segmented segments, a link layerheader may include a signaling class field, an information type field,and a signaling format field. The signaling class field may indicate asignaling target, the information type field may include data aboutsignaling information, and the signaling format field may indicate aformat of signaling information. The signaling class field, theinformation type field, and the signaling format field may be the sameas the aforementioned fields.

The aforementioned steps may be omitted or substituted with other stepsfor performing the similar/same operation in some embodiments.

FIG. 76 is a diagram illustrating an apparatus for transmitting abroadcast signal according to an embodiment of the present invention.

The apparatus for transmitting a broadcast signal according to anembodiment of the present invention may include a first module t76010, asecond module t76020, and/or a third module t76030.

The first module t76010 may generate a plurality of signalinginformation items. The first module may perform a procedurecorresponding to a step for generating a plurality of signalinginformation items. In addition, when segmentation is performed, thefirst module may perform a procedure corresponding to a step forgenerating signaling information for signaling the aforementionedbroadcast data in some embodiments.

The second module t76020 may generate a link layer packet using thegenerated signaling information items. The second module may perform aprocedure corresponding to a step for generating a link layer packetusing the aforementioned signaling information items. In addition, whensegmentation is performed, the second module may perform a procedurecorresponding to a step for generating a link layer packet using theaforementioned signaling information.

The third module t76030 may generate a broadcast signal using thegenerated link layer packet. In addition, the third module may transmitthe generated broadcast signal. The third module may perform operationscorresponding to a step for generating a broadcast signal using theaforementioned and a step for transmitting a broadcast signal. Inaddition, when segmentation is performed, the third module may performan operation corresponding to a step for generating a broadcast signalusing the aforementioned link layer packet and a step for transmittingthe broadcast signal in some embodiments.

The aforementioned first module, second module, and third module may beprocessors for executing consecutively performed procedures stored in amemory (or a storage unit). In addition, the aforementioned firstmodule, second module, and third module may be hardware elementspositioned in/outside the apparatus.

The aforementioned modules may be omitted or substituted with othersteps for performing the similar/same operation in some embodiments.

FIG. 77 is a diagram illustrating a configuration of a link layer packetwhen signaling information is transmitted to a link layer, according toanother embodiment of the present invention.

The present invention proposes a configuration of a link layer packetfor transmitting signaling information using a link layer packet. Inthis case, a value of the aforementioned packet type field may be 110.The signaling information may be encapsulated in a link layer using theconfiguration.

In the illustrated configuration t77010, a packet type field, a PCfield, an LI field, a segment ID field, a segment sequencer numberfield, a segment length ID field, and a last segment length field arethe same as the aforementioned fields. The concatenation count field maybe the aforementioned count field.

A header of the illustrated configuration (t77010) may further includeSignaling_Information_Part( ).

The Signaling_Information_Part( ) may be a combination of further addedfields with respect to a link layer packet for transmitting signalinginformation. The Signaling_Information_Part( ) may include detailedinformation about signaling information included in a payload of a linklayer. When the signaling information is multiplexed and transmitted,the current field may be used to determine whether correspondingsignaling information is processed and to determine a signalingprocessing module to which each signaling information item needs to betransmitted.

The Signaling_Information_Part( ) may be added when signalinginformation is contained in a link layer payload and may be referred toas an additional header for signaling information. In some embodiments,with regard to the current part, a configuration of fields included inthe part may be changed. According to the present embodiment, the partmay have a size of 1 byte or have different sizes in some embodiments.In some embodiments, when a plurality of signaling information items areconcatenated and included in a payload, Signaling_nformation_Part( ) maybe added by as much as the number indicated by the count field.

When a plurality of signaling information items are concatenated andincluded in a link layer payload, Signaling_Length fields indicating alength of each signaling information item may be added. TheSignaling_Length fields may exist by as much as the number ofconcatenated signaling information items, that is, the number indicatedby the count field. The Signaling_Length fields may indicate lengths ofrespective signaling information items. Here, the Signaling_Lengthfields may be positioned at the same order as an order of signalinginformation items included in a payload. The Signaling_Length field mayalso be referred to as a Component_Length field, and in the illustratedconfiguration (t77010), the Signaling_Length fields may be subsequent tothe Signaling_Information_Part( ), but an order thereof may be reversed.In addition, in the illustrated embodiment, the Signaling_Length fieldmay have a size of 2 bytes and may be embodied in some embodiments, anda padding bit for byte alignment may be further added.

The Signaling_Information_Part( ) may be variously configured, and thetwo configurations t77020 and t77030 are illustrated according toembodiments of the present invention. The present invention is notlimited to the embodiment.

In the first configuration (t77020), the Signaling_Information_Part( )may include a signaling class field (Signaling_Class) and/or a signalingformat field (Signaling_Format). The Signaling_Information_Part( ) maybe used when separate attribute of signaling information is not neededor there is corresponding information of signaling information.

In the second configuration (t77030), the Signaling_Information_Part( )may include a signaling class field, an information type field(Information_Type), and/or a signaling format field. In order toindicate more detailed information of signaling information, aninformation type field may be added.

In some embodiments, the two configurations may further include asignaling version field indicating a version of corresponding signalinginformation. In some embodiments, the two configurations may furtherinclude signaling encoding field indicating an encoding/compressionformat of corresponding signaling information. In some embodiments, onlyone signaling format may be used, or when a separate protocol forsignaling information exists and signaling formats are the same, thesignaling format field may be omitted. In the illustrated embodiments, abit number of each field is determined but this is merely an embodiment,and thus the bit number may be changed.

The signaling class field, the information type field, and the signalingformat field are the same as the aforementioned fields. Here, thesignaling class field may be referred as a Signaling_Type field, theinformation type field may be referred as a Signaling_Type_Extensionfield, and signaling format field may be referred as a Singnaling_Formatfield.

FIG. 78 is a diagram illustrating a Signaling_Class field when signalinginformation is transmitted to a link layer, according to anotherembodiment of the present invention.

Meaning according to embodiments of the aforementioned signaling classfield is illustrated. A type of signaling information indicated by eachfield may be determined when a signaling class field is 4 bits and 3bits. According to indication of the field, a type of signalinginformation included in a payload of a link layer may be indicated. Theillustrated indication of a field may be changed in some embodiments.

When the signaling class field has a value of 0000 or 000, acorresponding link layer payload may include signaling information forrapid channel scan such as fast information channel (FIC). In addition,the corresponding link layer payload may include signaling informationfor service acquisition.

When the signaling class field has a value of 0001 or 001, thecorresponding link layer payload may include signaling information foremergency alert such as an emergency alert system (EAS).

When the signaling class field has a value of 0010 or 010, thecorresponding link layer payload may include signaling informationassociated with header compression.

When the signaling class field has a value of 0011-1110 or 011-110,signaling information contained in the corresponding link layer payloadmay be reserved for future use. Through this, signaling informationitems to be added later may be determined.

When a signaling class field has a value of 1111 or 111, thecorresponding link layer payload may include a plurality of signalinginformation items. That is, when various types of signaling informationitems instead of a specific signaling information item are collected andtransmitted as one link layer packet, the link layer packet may beindicated through a specific value (1111 or 111) of a signaling classfield.

FIG. 79 is a diagram illustrating a Signaling_Class field and anInformation_Type field when signaling information is transmitted to alink layer, according to another embodiment of the present invention.

Meaning of a value of the information type field when the informationtype field is added to the Signaling_Information_Part( ) is illustrated.According to the present embodiment, it is assumed that the signalingclass field and the information type field are each 3 bits, but a lengthof each field may be changed in some embodiments, as described above.According to indication of the information type field, detailedinformation according to signaling information included in a link layerpayload may be indicated. Determination of the illustrated field valuemay be changed in some embodiments.

When the signaling class field has a value of 000, a corresponding linklayer payload may include signaling information for rapid channel scansuch as fast information channel (FIC) or signaling information forservice acquisition. In this case, when the information type field has avalue of 000, the value may indicate that the corresponding signalinginformation is signaling information for service acquisition in the caseof a value of 111 for signaling information for service scan. When theinformation type field has a value of 010-111, the information typefield may be reserved for future use.

When the signaling class field has a value of 001, a corresponding linklayer payload may include signaling information for emergency alert ofan emergency alert system (EAS) or the like. In this case, when theinformation type field has a value of 000, the corresponding signalinginformation may be an emergency alert message for emergency situation,when the information type field has a value of 001, the correspondingsignaling information may be link information of emergency alertmessage, when the information type field has a value of 010, thecorresponding signaling information may be automatic tuning information,when the information type field has a value of 011, the correspondingsignaling information may be NRT service information, and when theinformation type field has a value of 111, the corresponding signalinginformation may be wake-up indication information for activating areceiver. When the information type field has a value of 100-110, theinformation type field may be reserved for future use.

When the signaling class field has a value of 010, the correspondinglink layer payload may include signaling information associated withheader compression. In this case, when the information type field has avalue of 000, the corresponding signaling information may beinitialization information, when the information type field has a valueof 001, the corresponding signaling information may be configurationparameters, when the information type field has a value of 010, thecorresponding signaling information may be static chain, and when theinformation type field has a value of 011, the corresponding signalinginformation may be dynamic chain. When the information type field has avalue of 100-111, the information type field may be reserved for futureuse.

When the signaling class field has a value of 011-110, all values000-111 of the information type field may be reserved for future use.Accordingly, signaling information items to be added later may bedetermined.

When the signaling class field has a value of 111, the correspondinglink layer payload may include a plurality of signaling informationitems. In this case, detailed information items of signaling informationcannot be determined as one, and thus the signaling information may beindicated as default of 000. The remaining values 001-111 may bereserved for future use.

FIG. 80 is a diagram illustrating a Signaling_Format field whensignaling information is transmitted to a link layer, according toanother embodiment of the present invention.

The meaning of a value of a signaling format field is illustrated. It isassumed that the signaling format field is 4 bits and 2 bits, but thismay be changed in some embodiments, as described above. According toindication of a signaling format field, a format of correspondingsignaling information may be indicated. Determination of a value of theillustrated field may be changed.

The corresponding signaling information may have an ATSC signalingformat when a signaling format field of 4 bits has a value of 0000, thecorresponding signaling information may have a section table format whena signaling format field of 4 bits has a value of 0001, thecorresponding signaling information may have a descriptor field when asignaling format field of 4 bits has a value of 0010, the correspondingsignaling information may have a XML format when a signaling formatfield of 4 bits has a value of 0011, and the corresponding signalinginformation may have other formats when a signaling format field of 4bits has a value of 1111. When the signaling format field has a value of0100-1110, the signaling format field may be reserved for future use.

The corresponding signaling information may have an ATSC signalingformat when a signaling format field of 2 bits has a value of 00, thecorresponding signaling information may have a section table format whena signaling format field of 2 bits has a value of 01, the correspondingsignaling information may have a descriptor format when a signalingformat field of 2 bits has a value of 10, and the correspondingsignaling information may have other formats when a signaling formatfield of 2 bits has a value of 11.

According to a format of the signaling information, a bit number may beadjusted between fields of Signaling_Information_Part( ). In addition,whether future extension is emphasized according to a bit number of asignaling format field (high bit number) or whether only a signalingformat that is actually used in a broadcast system is determined (a lowbit number) may be determined.

Use of other formats may be used when the aforementioned signaling classfield is “Multiple signaling information”. That is, the other formatsmay be used when a plurality of signaling formats are mixed andconcatenated or can be processed by a module for parsing signalingwithout determination of a separate signaling format.

FIG. 81 is a diagram illustrating the case in which a plurality ofsignaling information items are concatenated with respect to aconfiguration of a link layer packet when signaling information istransmitted to a link layer, according to another embodiment of thepresent invention.

The configuration is illustrated in detail when a plurality of signalinginformation items is concatenated among configurations of a link layerpacket of the aforementioned signaling information. In the illustratedconfiguration, a size of each field indicated by a bit and a byte may bechanged in some embodiments.

The aforementioned fields may be positioned in a header of a link layerpacket. The packet type field may indicate that signaling information isincluded in a payload and the packet configuration field may indicate aconfiguration of a payload. The count field may indicate the number n ofa plurality of concatenated signaling information items. In someembodiments, a length information part indicated by a total length of alink layer payload may be additionally positioned prior to a countfield. In addition, an indicator indicating whether a correspondingpayload has a configuration using concatenation or a configuration usingsegmentation may be further positioned.

A header of a link layer packet may include the aforementionedSignaling_Information_Part( ). As described above, theSignaling_Information_Part( ) may have various configurations (t81010and t81020). Upon receiving a corresponding link layer packet, areceiver may process signaling information thereof usingSignaling_Information_Part( ) information of the header.

The header of the link layer packet may further include Signaling_Lengthfields indicating a length of each of concatenated signaling informationitems. The Signaling_Length field is the same as the aforementionedfield. In the illustrated configuration, the Signaling_Length fields maybe subsequent to the Signaling_Information_Part( ) but an order thereofmay be reversed. In addition, in the illustrated embodiment, theSignaling_Length field has a size of 2 bytes, but this is merely anembodiment and thus may be changed in some embodiments, and a paddingbit for byte alignment may be further added.

The Signaling_Information_Part( ) may have various configurationsaccording to the aforementioned embodiments (t81010 and t81020). It isassumed that a plurality of signaling information items with differentsignaling classes is transmitted in one link layer packet.

In this case, the signaling class field may have a value of 1111 or 111.The signaling format field may be determined in a format of concatenatedsignaling information items. For example, when a corresponding linklayer packet is applied to an ATSC system, the signaling format fieldmay have a value of 0000 or 00. When the information type field exists,the information type field may have a value of 000 as a default value.In this case, a receiver may not process a value of the information typefield.

Assuming that fields of a front part of a header is 1 byte,Signaling_Information_Part( ) is 1 byte, and Signaling_Length field is 2bytes, when a length of signaling information is L_(k) (k=1, 2, 3, . . ., n), a total length L_(T) of a link layer packet may be representedaccording to the illustrated equation (t81030).

FIG. 82 is a diagram illustrating a case in which a plurality ofsignaling information items are concatenated with respect to aconfiguration of a link layer packet when signaling information istransmitted to a link layer, according to another embodiment of thepresent invention.

The present embodiment may be the same as the aforementioned case inwhich a plurality of signaling information items are concatenated,except that Signaling_Information_Part( ) and Signaling_Length field ofsignaling information exist. The number of subsequentSignaling_Information_Part( ) and Signaling_Length field may bedetermined according to the number indicated by the count field, and anorder may be the same as an order of the corresponding concatenatedsignaling information items. In some embodiments,Signaling_Information_Part( ) items may be positioned only in a frontpart and Signaling_Length field items may be positioned only in a rearpart. In addition, in some embodiments, an order ofSignaling_Information_Part( ) and Signaling_Length field may be revered.

Each signaling information item may be represented by a pair ofSignaling_Information_Part( ) and Signaling_Length field. Upon receivinga corresponding link layer packet, a receiver may check separatesignaling information and may separately process each signalinginformation item.

According to the aforementioned embodiment of the present invention, theSignaling_Information_Part( ) may have various configurations (t82010and t82020). It is assumed that a plurality of signaling informationitems with different signaling classes is transmitted as one link layerpacket.

Since different signaling information items can be separatelyrepresented, a signaling class field, an information type field, and asignaling format field may be determined with respect to each signalinginformation item. In this case, a value indicating “multiple signalinginformation” of the signaling class field does not have to be used, anda corresponding value may be used with different meaning.

Assuming fields of a front part of a header are 1 byte,Signaling_Information_Part( ) is 1 byte, and Signaling_Length field is 2bytes, when a length of the signaling information is L_(k) (k=1, 2, 3, .. . , n), a total length L_(T) of a link layer packet may be representedaccording to the illustrated equation (t82030).

FIG. 83 is a diagram illustrating a configuration of a link layer packetwhen a framed packet is transmitted to a link layer, according toanother embodiment of the present invention.

The present invention proposes a configuration of a link layer packetfor transmitting an Ethernet packet using a link layer packet withrespect to the Ethernet packet used in a general network instead of abroadcast packet such as IP or MPEG-2 TS. In addition, the presentinvention proposes a method for indicating a protocol type of thecorresponding Ethernet packet. In this case, a value of theaforementioned packet type field may be 111. Ethernet packets may beencapsulated in a link layer using the configuration. The Ethernetpackets may be referred to as a framed packet.

In the illustrated configuration, the packet type field, the PC field,the LI field, the segment ID field, the segment sequencer number field,the segment length ID field, and the last segment length field are thesame as the aforementioned fields. The concatenation count field may bethe same as the aforementioned count field.

A header of the illustrated configuration may further include anEthernet type field.

The Ethernet type field may be a field that is further added to a linklayer packet for transmitting a framed packet. The Ethernet type fieldmay include detailed information about a protocol and type of a framedpacket included in a link layer payload.

Here, with respect to the protocol, values registered in an IANA may bedetermined. The Ethernet type field may be referred to as an additionalheader for type extension. According to the present embodiment, thefield may have 2 bytes or a variable size.

According to the present embodiment, when a plurality of framed packetsare concatenated and included in a payload, Ethernet type fields may beadded by as much as the number indicated by the count field. Inaddition, length fields indicating a length of each framed packet may beadded by as much as the n umber indicated by the count field. Acombination of the length fields may be referred to as a payload lengthpart.

Here, length fields may be positioned at the same order as an order offramed packets included in a payload. The length field may be referredto as Component_Length field, and in the illustrated configuration, thelength fields may be subsequent to the Ethernet type field but an orderthereof may be reversed. In addition, in some embodiments, the lengthfield may have a size of 2 bytes or different sizes, and a padding bitfor byte alignment may be further added.

When one framed packet is segmented, the Ethernet type field may beadded to only a first segment. The receiver can recombine an originalframed packet using an Ethernet type field of a first segment.

FIG. 84 is a diagram illustrating ethernet_type field when a framedpacket is transmitted to a link layer, according to another embodimentof the present invention.

As described above, the Ethernet type field may indicate a protocol andtype of a framed packet included in a link layer payload. Theillustrated table shows an Ethernet type value defined by IANA withrespect to a main protocol.

For example, when a value of the Ethernet type field is 0x0800, theframed packet may be a packet of Internet Protocol version 4 (IPv4),when a value of the Ethernet type field is 0x0806, the framed packet maybe an address resolution protocol (ARP) type, and when a value of theEthernet type field is 0x0842, the framed packet may be a Wake-on-LANtype. Indication by the Ethernet type field may be variously configuredand the present invention is not limited thereto.

FIG. 85 is a diagram illustrating the case in which one input packet isincluded in a link layer payload when a framed packet is transmitted toa link layer, according to another embodiment of the present invention.

It is assumed that an input framed packet is within a processing rangeof a physical layer and one link layer payload is directly configuredwithout concatenation or segmentation.

The fields are the same as the aforementioned fields. According to thepresent embodiment, a value of the packet type field may be 111 and avalue of the PC field may be 0. A value of the count field may be 0000.In some embodiments, when one packet is included in a payload, the countfield may be omitted.

A header may include an Ethernet type field and/or a payload lengthpart. In some embodiments, an order of the two fields may be reversed.The Ethernet type field may indicate a protocol and type of a framedpacket included in a payload. The payload length part may include onelength field and indicate a length of a framed packet, that is, a totallength of a payload.

In some embodiments, a value of fields is variable, but 5 bytes are usedas a link layer header in the illustrated embodiment, and thus when alength of a framed packet is L bytes, a total length of the link layerpacket may be (L+5) bytes.

FIG. 86 is a diagram illustrating the case in which a plurality of inputpackets are concatenated and included in a link layer payload when aframed packet is transmitted to a link layer, according to anotherembodiment of the present invention.

When an input framed packet does not reach a processing range of aphysical layer, each framed packet may be concatenated and included in alink layer payload.

The fields may be the same as the aforementioned fields. Here, a linklayer header may be variously configuration according to configurationsof the Ethernet type field and the length fields.

A First configuration (not shown) is a configuration in which framedpackets with the same Ethernet type are concatenated and included in apayload. In this case, a link layer header may include one Ethernet typefield. The Ethernet type field may include a protocol/type of acorresponding framed packet. A plurality of length fields may bepositioned in a front or rear part of the Ethernet type field. Thelength fields may indicate a length of a concatenated framed packet.

A second configuration t86010 is a configuration in which framed packetswith different Ethernet types are concatenated and included in apayload. In this case, Ethernet type fields and length fields, thenumber of which is the same as the number of concatenated framedpackets, may be included in a header. The Ethernet type fields and thelength fields may indicate a type and length of the corresponding framedpacket in the stated order. Assuming that fields of a front part of aheader is 1 byte, an Ethernet type field is 2 bytes, and length fieldsare each 2 byes, when a length of a framed packet is L_(k) (k=1, 2, 3, .. . , n), a total length L_(T) of a link layer packet may be representedaccording to the illustrated equation (t86020).

A third configuration t86030 corresponds to a configuration according toanother embodiment of the present invention in which framed packets withdifferent Ethernet types are concatenated and included in a payload. Inthis case, Ethernet type fields and length fields, the number of whichis the same as the number of concatenated framed packets, may also beincluded in a header. Here, the Ethernet type fields and the lengthfields may be alternately positioned in a header. In the illustratedconfiguration, Ethernet type field #1 and length field #1 for framedpacket #1 may be paired and included in a header. In some embodiments,the length field may be positioned in front of the Ethernet type field.An order of pairs may be the same as an order of concatenated framedpackets.

FIG. 87 is a diagram illustrating the case in which one input packet issegmented and included in a link layer payload when a framed packet istransmitted to a link layer, according to another embodiment of thepresent invention.

When an input framed packet exceeds a processing range of a physicallayer, one framed packet may be segmented to a plurality of segments.The fields may be the same as the aforementioned fields. Like in thecase in which the IP packet is segmented, when a framed packet issegmented, CRC encoding may also be used. The CRC may be added to a lastpart of the framed packet. When a receiver recombines a framed packet,the CRC may be used to check integrity of recombination. When framedpackets to which CRC is added are segmented, a link layer packetincluding a last segment may also include CRC.

In general, the CRC may be added to a last part of a packet and may beadded to other positions in some embodiments.

In the aforementioned embodiments, in the case of segmentation, a lengthof the link layer payload may be calculated according to values of asegment length ID field and a last segment length fields. However, insome embodiments, a link layer header may simply include a fieldindicating a length of a link layer payload. In the method, the methodmay be used when one input packet is included or concatenated in apayload.

FIG. 88 is a diagram illustrating a method for transmitting a broadcastsignal according to an embodiment of the present invention.

According to an embodiment of the present invention, the method fortransmitting the broadcast signal may include generating a plurality ofinput packets including broadcast data, generating a link layer packetusing the input packet, generating a broadcast signal, and/ortransmitting the broadcast signal.

First, a first module of a service provider side may generate aplurality of input packets (t88010). Here, a plurality of input packetsmay be an MPEG2-TS packet, an IP packet, or a specific type of packet ormay be defined and used in the future. The first module may be aspecific module that generates broadcast data in the form of inputpackets.

A second module of a service provider may generate at least one linklayer packet using a plurality of input packets (t88020). This maycorrespond to the aforementioned procedure for generating a link layerpacket by encapsulating input packets in a link layer. Here, the linklayer packet may have a packet configuration according to theaforementioned embodiments.

According to the present embodiment, a header of a link layer packet mayinclude packet type information and packet configuration information.The packet type information may indicate a type of an input packetincluded in a payload of a link layer packet and the packetconfiguration information may indicate a configuration of a payload of alink layer packet. The packet type information may correspond to theaforementioned packet type field and the packet configurationinformation may correspond to the aforementioned packet configurationfield (PC).

A third module of a service provider side may generate a broadcastsignal using the generated link layer packet (t88030). This maycorrespond to an operation such as interleaving, framing, and so onusing a link layer packet in a physical layer. A fourth module of aservice provider side may transmit the generated broadcast signal. Here,the fourth module may correspond to an antenna or the like.

According to another embodiment of the present invention, in the methodfor transmitting the broadcast signal, when a payload includes one ofsegmented segments of an input packet, a header may further includeinformation about a segment sequencer number indicating an order in acorresponding input packet of a segment included in a link layer packet.This may correspond to the aforementioned segmentation. The segmentsequencer number information may correspond to the aforementionedsegment sequencer number field.

According to another embodiment of the present invention, in the methodfor transmitting the broadcast signal, a header may further include alast segment indicator indicating whether a segment included in a linklayer packet is a last segment of a corresponding input packet. This maycorrespond to the aforementioned segmentation. Here, the last segmentindicator may correspond to the aforementioned last segment lengthfield.

According to another embodiment of the present invention, in the methodfor transmitting the broadcast signal, when a payload includes aplurality of input packets, a header may further include countinformation indicating the number of input packets included in a linklayer packet. This may correspond to the aforementioned concatenation.Here, the count information may correspond to the aforementioned count.

According to another embodiment of the present invention, in the methodfor transmitting the broadcast signal, a header may further includecomponent length information indicating a length of each input packetincluded in a link layer packet. This may correspond to theaforementioned concatenation. Here, component length information itemsmay correspond to respective length fields of the aforementioned inputpackets.

According to another embodiment of the present invention, in the methodfor transmitting the broadcast signal, component length informationitems may be positioned at the same order as an order at whichcorresponding input packets are positioned in a payload. This maycorrespond to the aforementioned concatenation. According to the presentembodiment, length fields may be positioned at the same order as anorder of concatenated input packets and may indicate lengths of inputpackets.

According to another embodiment of the present invention, in the methodfor transmitting the broadcast signal, a plurality of input packets mayinclude signaling data including broadcast data. In this case, a headermay further include signaling type information, signaling type extensioninformation, and signaling format information. The signaling typeinformation may indicate a type of signaling data, the signaling typeextension information may indicate property of signaling data, and thesignaling format information may indicate a format of signaling data.These information items may correspond to the aforementioned signalingclass field, information type field, and signaling format field.

According to another embodiment of the present invention, in the methodfor transmitting the broadcast signal, packet type information of aheader may indicate that an input packet included in a link layer packetis an extended packet, and a header may further include extension typeinformation indicating a protocol or type of an extension packet. Thismay correspond to the case in which a framed packet is transmitted to alink layer among the aforementioned embodiments. In this case, a valueof the aforementioned packet type field may be 111. Here, the extendedpacket may be the aforementioned framed packet and Ethernet packet.Here, the extension type information may correspond to theaforementioned Ethernet type field.

According to another embodiment of the present invention, in the methodfor transmitting the broadcast signal, a payload may include one inputpacket and a header may further include length information indicating alength of a payload of a link layer packet. This may correspond to thecase in which the aforementioned single packet, that is, one inputpacket is included in a payload without segmentation/concatenation.Here, the length information may correspond to a length field indicatinga length of the aforementioned payload.

According to an embodiment of the present invention, a method forreceiving a broadcast signal will now be described. The method is notillustrated.

According to an embodiment of the present invention, the method forreceiving the broadcast signal may include receiving a broadcast signal,acquiring a link layer packet of a broadcast signal, and/or generatingan output packet using the link layer packet.

First, a first module of a receiver side may receive a broadcast signal.The broadcast signal may be a broadcast signal transmitted by a serviceprovider side according to the aforementioned embodiment. The firstmodule may be a receiving apparatus such as an antenna or a tuner.

A second module of a receiver side may acquire a link layer packet usingthe received broadcast signal. The link layer packet may be the same asthe aforementioned link layer packet. This procedure may correspond to aprocedure for processing a broadcast signal in a physical layer of areceiver side to output an output stream to a link layer.

Then a third module of the receiver side may process a link layer packetto generate an output packet. Here, the output packet may correspond toan input packet transmitted to a link layer by a service provider. Inthis procedure, packets encapsulated in the link layer packet may berestored. The procedure may correspond to an opposite procedure of theaforementioned “step for generating a link packet using input packets”.

According to an embodiment of the present invention, in the method forreceiving a broadcast signal and a method according to other embodimentsof the present invention, a link layer packet may have theaforementioned configuration/information items. That is, a configurationof a link layer packet and fields/information items included thereinthat are described in the aforementioned embodiment of a serviceprovider side.

The aforementioned steps may be omitted or substituted with other stepsfor performing the similar/same operation in some embodiments.

FIG. 89 is a diagram illustrating an apparatus for transmitting abroadcast signal according to an embodiment of the present invention.

According to an embodiment of the present invention, the apparatus fortransmitting the broadcast signal may include the aforementioned firstmodule, second module, third module, and/or fourth module. The modulesare the same as the aforementioned modules.

The apparatus for transmitting the broadcast signal according to anembodiment of the present invention and modules/blocks installed thereinmay perform the aforementioned method for transmitting a broadcastsignal.

An apparatus for receiving a broadcast signal according to an embodimentof the present invention will be described below. The apparatus forreceiving the broadcast signal according to an embodiment of the presentinvention is not illustrated.

The apparatus or receiving content according to an embodiment of thepresent invention may include the aforementioned first module, secondmodule, and/or third module. The modules may be the same as theaforementioned modules.

According to an embodiment of the present invention, the apparatus forreceiving the broadcast signal and modules/blocks installed therein mayperform the aforementioned method for receiving a broadcast signal.

The aforementioned blocks/modules installed in the apparatus fortransmitting a broadcast signal and the apparatus for receiving thebroadcast signal may be processors for executing consecutively performedprocedures stored in a memory or may be hardware elements disposedoutside the apparatus in some embodiments.

The aforementioned modules may be omitted or substituted with othersteps for performing the similar/same operation in some embodiments.

A module or a unit may be processors for executing consecutivelyperformed procedures stored in a memory (or a storage unit). Inaddition, the steps according to the aforementioned embodiments of thepresent invention may be performed by hardware/processor. Eachmodule/block/unit according to the aforementioned embodiments of thepresent invention may function as a hardware/processor. In addition, themethods proposed by the present invention may be executed as a code. Thecode can be written in a storage medium readable by a processor and thuscan be read by a processor provided by an apparatus.

For convenience of description, the drawings are separately describedbut a new embodiment may be designed by combining embodimentsillustrated in the drawings. In addition, according to necessity ofthose skilled in the art, design of a computer readable recording mediumwith a program recorded therein for executing the aforementionedembodiments is within the scope of the spirit of the invention.

As described above, an apparatus and a method according to the presentembodiment may be configured by selectively combining all or some of theaforementioned embodiments for various modifications rather than beingrestrictively limited.

The method proposed by the present invention may be embodied as a codereadable by a processor in a recording medium readable by a processorincluded in a network device. The recording medium readable by theprocessor may include any type of recording apparatus in which datareadable by a processor is stored. Examples of the recording mediumreadable by the processor may include a ROM, a RAM, a CD-ROM, a magnetictape, a floppy disk, and an optical data storage device and embodied inthe form of a carrier wave in a transmission through the Internet. Theprocessor readable recording medium can also be distributed over networkcoupled computer systems so that the computer readable code is storedand executed in a distributed fashion.

While the present invention has been particularly shown and describedwith reference to exemplary embodiments thereof, it will be understoodby those of ordinary skill in the art that various changes in form anddetails may be made therein without departing from the spirit and scopeof the present invention as defined by the following claims and themodifications may not be separately understood from the spirit and scopeof the present invention.

In addition, in the specification, the present invention has beendescribed in terms of an apparatus and a method, and as necessary, theapparatus and the method may be supplementarily applied.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present inventionwithout departing from the spirit or scope of the invention. Thus, it isintended that the present invention cover the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

In addition, in the specification, the present invention has beendescribed in terms of both an apparatus and a method, and as necessary,the apparatus and the method may be supplementarily applied.

[Mode for Invention]

Various embodiments have been described in the Best Mode forimplementing the present invention.

INDUSTRIAL APPLICABILITY

The present invention has industrial applicability in a predeterminedindustrial field associated with a method for transmitting a broadcastsignal, a method for receiving a broadcast signal, an apparatus fortransmitting a broadcast signal, and an apparatus for receiving abroadcast signal.

The invention claimed is:
 1. A method for transmitting a broadcastsignal, the method comprising: generating input packets comprisingbroadcast data; generating link layer packets by encapsulating the inputpackets, wherein a link layer packet includes a base header and apayload, wherein the base header includes packet type information andconfiguration type information, the packet type information indicates atype of data encapsulated in the payload, and the configuration typeinformation indicates configuration of the payload, wherein the typeindicated by the packet type information corresponds to one of InternetProtocol (IP) packet, compressed IP packet, signaling packet,MPEG-2transport stream packet and type extension; generating thebroadcast signal including the link layer packets; and transmitting thebroadcast signal, wherein the link layer packet further includes anadditional header, wherein the additional header includes either asegmentation information part including segment sequence numberinformation for indicating a sequence number of a segment of an inputpacket or a concatenation information part including component lengthelements for indicating a length of each of concatenated input packetsdepending on whether the configuration type information indicates thatthe payload encapsulates the segment of the input packet or theconcatenated input packets, wherein when the configuration typeinformation indicates that the payload encapsulates the concatenatedinput packets, the link layer packet further includes count informationfor indicating a number of the concatenated input packets, wherein avalue of the count information is set to the number of the concatenatedinput packets minus two, and wherein when the packet type informationindicates that the type extension is used, packet type extensioninformation is further included in the additional header, the packettype extension information indicates a type of the input packetsencapsulated in the payload.
 2. The method according to claim 1, whereinthe packet type information has a predefined value when indicating thatthe type extension is used.
 3. The method according to claim 1, whereinthe component length elements are positioned in the same order as thecorresponding input packets positioned in the payload.
 4. An apparatusfor transmitting a broadcast signal, the apparatus comprising: a firstmodule configured to generate input packets comprising broadcast data; asecond module configured to generate link layer packets by encapsulatingthe input packets, wherein a link layer packet includes a base headerand a payload, wherein the base header includes packet type informationand configuration type information, the packet type informationindicates a type of data encapsulated in the payload, and theconfiguration type information indicates configuration of the payload,wherein the type indicated by the packet type information corresponds toone of Internet Protocol (IP) packet, compressed IP packet, signalingpacket, MPEG-2transport stream packet and type extension; a third moduleconfigured to generate the broadcast signal including the link layerpackets; and a fourth module configured to transmit the broadcastsignal, wherein the link layer packet further includes an additionalheader, wherein the additional header includes either a segmentationinformation part including segment sequence number information forindicating a sequence number of a segment of an input packet or aconcatenation information part including component length elements forindicating a length of each of concatenated input packets depending onwhether the configuration type information indicates that the payloadencapsulates the segment of the input packet or the concatenated inputpackets, wherein when the configuration type information indicates thatthe payload encapsulates the concatenated input packets, the link layerpacket further includes count information for indicating a number of theconcatenated input packets, wherein a value of the count information isset to the number of the concatenated input packets minus two, andwherein when the packet type information indicates that the typeextension is used, packet type extension information is further includedin the additional header, the packet type extension informationindicates a type of the input packets encapsulated in the payload. 5.The apparatus according to claim 4, wherein the packet type informationhas a predefined value when indicating that the type extension is used.6. The apparatus according to claim 4, wherein the component lengthelements are positioned in the same order as the corresponding inputpackets positioned in the payload.
 7. A method for receiving a broadcastsignal, the method comprising: receiving the broadcast signal; obtaininglink layer packets from the broadcast signal, wherein a link layerpacket includes a base header and a payload, wherein the base headerincludes packet type information and configuration type information, thepacket type information indicates a type of data encapsulated in thepayload, and the configuration type information indicates configurationof the payload, wherein the type indicated by the packet typeinformation corresponds to one of Internet Protocol (IP) packet,compressed IP packet, signaling packet, MPEG-2transport stream packetand type extension; and obtaining input packets by decapsulating thelink layer packets, wherein the input packets comprise broadcast data,wherein the link layer packet further includes an additional header,wherein the additional header includes either a segmentation informationpart including segment sequence number information for indicating asequence number of a segment of an input packet or a concatenationinformation part including component length elements for indicating alength of each of concatenated input packets depending on whether theconfiguration type information indicates that the payload encapsulatesthe segment of the input packet or the concatenated input packets,wherein when the configuration type information indicates that thepayload encapsulates the concatenated input packets, the link layerpacket further includes count information for indicating a number of theconcatenated input packets, wherein a value of the count information isset to the number of the concatenated input packets minus two, andwherein when the packet type information indicates that the typeextension is used, packet type extension information is further includedin the additional header, the packet type extension informationindicates a type of the input packets encapsulated in the payload.
 8. Anapparatus for receiving a broadcast signal, the apparatus comprising: afirst module configured to receive the broadcast signal; a second moduleconfigured to obtain link layer packets from the broadcast signal,wherein a link layer packet includes a base header and a payload,wherein the base header includes packet type information andconfiguration type information, the packet type information indicates atype of data encapsulated in the payload, and the configuration typeinformation indicates configuration of the payload, wherein the typeindicated by the packet type information corresponds to one of InternetProtocol (IP) packet, compressed IP packet, signaling packet,MPEG-2transport stream packet and type extension; and a third moduleconfigured to obtain input packets by decapsulating the link layerpackets, wherein the input packets comprise broadcast data, wherein thelink layer packet further includes an additional header, wherein theadditional header includes either a segmentation information partincluding segment sequence number information for indicating a sequencenumber of a segment of an input packet or a concatenation informationpart including component length elements for indicating a length of eachof concatenated input packets depending on whether the configurationtype information indicates that the payload encapsulates the segment ofthe input packet or the concatenated input packets, wherein when theconfiguration type information indicates that the payload encapsulatesthe concatenated input packets, the link layer packet further includescount information for indicating a number of the concatenated inputpackets, wherein a value of the count information is set to the numberof the concatenated input packets minus two, and wherein when the packettype information indicates that the type extension is used, packet typeextension information is further included in the additional header, thepacket type extension information indicates a type of the input packetsencapsulated in the payload.